JP5995709B2 - In-vehicle motor cooling system - Google Patents

Description

  The present invention relates to an in-vehicle motor cooling apparatus that transfers a cooling medium to a motor mounted on a vehicle for cooling.

  In recent years, in vehicles such as automobiles, a hybrid vehicle (HEV) that runs using an engine and a motor as a power source and an electric vehicle (EV) that runs using only a motor as a power source have been developed from the viewpoint of low pollution and resource saving. . In these vehicles, lubricating oil is supplied to a motor and a transmission mechanism by an oil pump or the like to cool and lubricate each part, and it is necessary to operate the oil pump at an appropriate timing.

  For this reason, for example, in Patent Document 1, the engine output is transmitted to the driving wheels and the motor generator mechanism, and the engine output shaft can be forcibly rotated by the motor generator mechanism, and is directly connected to the engine output shaft. In a hybrid vehicle having an oil pump, during EV traveling, the rotational torque of the motor generator mechanism is transmitted to a rotating shaft for operating the oil pump at a predetermined timing, whereby the oil pump is operated for a certain period of time and the power split mechanism The lubricant oil is supplied to the power splitting mechanism at an appropriate timing even during EV traveling, and when the oil pump is stopped, the lubricant oil is supplied to the power split mechanism. A technique for preventing burning at a portion where the supply is stopped is disclosed.

Japanese Patent No. 3722102

  In HEV and EV, in particular, the motor generates heat during operation, and the output performance is limited by the temperature rise caused by the generated heat. Therefore, it is extremely important to cool the motor appropriately. Conventionally, however, the temperature of the motor is estimated by measuring the temperature of oil for cooling the motor because it is difficult to directly measure the temperature of a rotating body such as an internal rotor. When the internal temperature rises rapidly, there is a risk that even if the oil temperature is measured, a response delay occurs and cooling cannot be started properly.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cooling device for an in-vehicle motor capable of accurately grasping the temperature of the motor without a response delay and cooling the motor at an appropriate timing.

An on-vehicle motor cooling device according to the present invention includes an on-vehicle motor cooling device that transfers a cooling medium to a motor mounted on a vehicle via a transfer device to cool the motor. The amount of electric power generated by the motor is monitored every predetermined unit time as the amount of motor electric power, and the motor electric power monitoring unit for integrating the electric motor electric energy, and the transfer device integrated by the motor electric power monitoring unit to the motor From a motor cooling determination unit that determines whether or not forced cooling of the motor is necessary based on an integrated value of the motor electric energy from the stop of the transfer of the cooling medium to the present, and from the motor cooling determination unit the instruction is to drive the front KiUtsuri feeding devices that a motor cooling control unit for forcibly cooling the motor.

  According to the present invention, the temperature of the motor can be accurately grasped without a response delay, and the motor can be cooled at an appropriate timing.

HEV system configuration diagram Explanatory diagram showing the relationship between the integrated power value and the cooling start timing Explanatory drawing which shows the relationship between the electric power integration amount per fixed time and cooling start timing Motor cooling control process flowchart

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a vehicle drive system to which the present invention is applied. In this embodiment, a hybrid vehicle (HEV) HEV system that uses an engine 2 and a motor 3 together. In the example of FIG. 1, an engine 2 and a motor 3 are arranged in series via a clutch 4, and a transmission 5 is connected to the output side of the motor 3. The driving force output from the transmission 5 is transmitted to both or one of the front wheels 6F and the rear wheels 6R.

  The engine 2 is an internal combustion engine that generates power using, for example, gasoline or the like as fuel. The motor 3 is a synchronous generator including, for example, a rotor 3a made of a permanent magnet supported on an output shaft that is rotatably supported and a stator 3b around which a three-phase winding is wound. The motor 3 generates motive power by the electric power from the battery 100, and generates electric power when the engine 2 is driven or the regenerative brake is operated, thereby charging the battery 100.

  The hybrid vehicle 1 is controlled by an electronic control system including a plurality of electronic control units centered on a hybrid control unit (HCU) 101. That is, the HCU 101 controls a motor controller 102 that controls the motor 3 via the inverter 103, an engine control unit (ECU) 104 that controls the engine 2, a transmission control unit 105 that controls the clutch 4 and the transmission 5. By controlling the entire vehicle drive system, it is possible to switch between running with the power of only the motor 3 with the clutch 4 opened and running with the power of the engine 2 and the motor 3 with the clutch 4 engaged.

  1 is connected to sensors (not shown) for detecting the driving state of the vehicle and various actuators such as various control valves of the hydraulic system.

  Moreover, the hybrid vehicle 1 shown in FIG. 1 is a hybrid vehicle equipped with a charging circuit (charging device) 106 for charging the battery 100 and capable of being charged from a household power source. That is, the battery 100 is connected to a charging circuit (charging device) 106 including a household power plug 107. The charging circuit 106 receives power from the household power supply via the household power plug 107 and charges the battery 100.

  Here, the motor 3 and the transmission 5 are cooled and lubricated by lubricating oil supplied by an oil pump 7 as a transfer device for transferring a cooling medium to the motor 3. The oil pump 7 is composed of, for example, a trochoid pump, a gear pump, etc., and is driven by the engine 2 or a motor (not shown) and sucks the lubricating oil stored in the oil pan 8. The lubricant is pumped to the power system. The lubricating oil pumped from the oil pump 7 circulates through the gear elements and the rotating portions and sliding portions of the shafts to reduce the frictional resistance and cool the respective portions.

  For this reason, the HCU 101 is mainly provided with functions represented by a motor power monitoring unit 101a, a motor cooling determination unit 101b, and a motor cooling control unit 101c as functions related to the cooling control processing of the motor 3, as shown in FIG. ing. Note that these functions may be provided in a control unit other than the HCU 101.

  In this embodiment, an example in which the motor 3 is cooled by an oil cooling method using oil as a cooling medium will be described. However, the motor 3 may be cooled by a water cooling method using water as a cooling medium. In the oil cooling system, since the cooling medium has insulating properties, it is possible to cool the heat generating parts (coil, core, magnet, etc.) of the motor directly by circulating oil inside the motor. In the case of a cooling structure in which oil enters, it is necessary to pay attention to the frictional resistance of the oil.

  The motor power monitoring unit 101a determines the amount of power supplied to the motor 3 during EV travel (including reverse travel) of only the motor 3, or the amount of power generated when regenerative travel or when driven as a generator by the engine 2. Monitor every unit time. Specifically, the power consumed by the motor 3 or the power generated by power generation (including regeneration) is recorded in time series as the motor power amount w per unit time, and after the cooling by the oil pump 7 is stopped, A power amount (a power amount WT and a power integration value WS to be described later) obtained by integrating the motor power amount w is calculated.

  The motor cooling determination unit 101b determines whether or not forced cooling of the motor 3 is necessary based on the amount of power calculated by the motor power monitoring unit 101a, and instructs the motor cooling control unit 101c to start cooling of the motor 3. The necessity of cooling of the motor 3 depends on the integrated power value WS from the stop of the transfer of the lubricating oil to the motor 3 by the oil pump 7 and a certain time T (for example, a few seconds) on the way. WT (accumulated value of time T of motor electric energy w per unit time) WT.

  In general, motor heat generation is caused by mechanical loss such as copper loss and iron loss due to conductive material and magnetic material, friction of bearings and air stirring resistance in the air gap between the rotor and stator. Inevitably occurs. Of these losses, the mechanical loss is usually smaller than the copper loss and iron loss, and since known measures can be taken in advance, the copper loss and iron due to the motor current that changes according to the driving state of the vehicle. Loss is the dominant factor in motor heat generation.

  Therefore, the temperature rise inside the motor due to the heat generated by the operation of the motor 3 can be estimated by the integrated power value WS of the motor 3 up to the present, and the integrated power value WS up to the present is continuously detected by the motor 3. Whether or not the motor 3 needs to be cooled can be determined by comparing with a threshold value WSH that defines the operable temperature state. The threshold value WSH is set in advance by experiments or simulations in consideration of the heat dissipation characteristics taking into consideration the heat capacity of the motor 3, and when the integrated power value WS exceeds the threshold value WSH, it is necessary to forcibly cool the motor 3. If it is determined that there is, the oil pump 7 is operated by instructing the motor cooling control unit 101c.

  That is, as shown in FIG. 2, the power integrated value WS represented by the area of the curve indicating the motor power amount w per unit time is the motor power per unit time as indicated by WS1 and WS2 in FIG. When the amount w is large, timings (time) T1 and T2 that exceed the threshold value WSH in each case are T1 <T2 as compared with the case where the motor power amount w per unit time is small. Therefore, by monitoring the power integrated value WS obtained by integrating the motor electric power w per unit time, the internal temperature of the motor that is difficult to measure can be accurately grasped, and the motor cooling can be started at an appropriate timing. Is possible.

  Further, as shown in FIG. 3, in a component such as the rotor 3a of the motor 3, the temperature Tp of the component is rapidly increased according to the load. For this reason, the cooling of the rapidly rising component is not in time (the temperature Toil of the lubricating oil for cooling rises relatively slowly), and the allowable temperature Tpmax of the corresponding component in a short time as shown by the broken line in FIG. May be exceeded.

  Therefore, the power amount WT obtained by integrating the motor power amount w per unit time for a fixed time T is compared with a preset threshold value WTH, and when the power amount WT per fixed time T exceeds the threshold value WTH, the motor 3 is turned on. It is determined that it is necessary to forcibly cool, and the motor cooling control unit 101c is instructed to operate the oil pump 7. The threshold value WTH is set in advance by experiments or simulations in consideration of the allowable temperature Tpmax of components such as the rotor 3a inside the motor 3.

  The motor cooling control unit 101c starts the oil pump 7 in accordance with an instruction from the motor cooling determination unit 101b and transfers the lubricating oil to the motor 3 and the transmission 5 to cool each part and lubricate the rotation / sliding part. . When the oil pump 7 is an engine drive type, the motor cooling control unit 101c instructs the ECU 104 to start the engine 2. When the oil pump 7 is a motor drive type, the motor cooling control unit 101c does not show the illustration. The motor is driven via the drive circuit, and the oil pump 7 is started.

  Specifically, the motor cooling control process by the above functional units is realized by a program process executed by the HCU 101. Next, motor cooling control program processing will be described with reference to the flowchart shown in FIG.

  The motor cooling control process shown in the flowchart of FIG. 4 is a process executed at a predetermined time period. In the first step S1, it is checked whether or not the oil pump 7 is stopped. When the oil pump 7 is driven and the lubricating oil is supplied to the motor 3 and the transmission 5 and each part is cooled and lubricated, the process jumps from step S1 to step S7, and as described later, It is checked whether or not a condition for stopping the pump 7 is satisfied.

  On the other hand, when the oil pump 7 is stopped in step S1, the process proceeds from step S1 to step S2, the motor power amount w per unit time is monitored, and the motor power amount w per unit time is integrated. Go. The motor power consumption w is monitored at least with the execution cycle of this process as a unit time.

  Thereafter, the process proceeds to step S3, and it is checked whether or not the electric energy WT per fixed time T exceeds a threshold value WTH as a first threshold value. As a result, if WT> WTH in step S3, the process proceeds to step S5, the oil pump 7 is started via the engine 2 or a motor (not shown), and lubricating oil is supplied to the motor 3 and the transmission 5. That is, if it is expected that the load on the motor 3 will temporarily increase and the temperature of the rotor 3a of the motor 3 will rise excessively, the oil pump 7 is started immediately, thereby forcibly cooling the motor 3. Do.

  If WT ≦ WTH in step S3, it is further determined in step S4 whether or not the integrated power value WS of the motor power amount per unit time up to the present time exceeds a threshold value WSH as the second threshold value. Investigate. If WS ≦ WSH, the process is exited. If WS> WSH, the process proceeds to step S5 to start the oil pump 7. That is, when the motor temperature is expected to exceed the upper limit by using the motor 3 for a long period of time, the oil pump 7 is started to forcibly cool the motor 3.

  After starting the oil pump 7 in step S5, the monitor data of the motor power amount w is cleared in step S6, and it is checked in step S7 whether the stop condition of the oil pump 7 is satisfied. The oil pump stop condition is determined based on, for example, the oil temperature of the lubricating oil around the motor 3, and when the detected oil temperature falls below a predetermined set temperature, the temperature of the motor 3 falls below a temperature that requires forced cooling. It is determined that the oil pump 7 has been lowered, and the oil pump 7 is stopped.

  If the stop condition for the oil pump 7 is not satisfied in step S7, the process is temporarily exited. If the stop condition for the oil pump 7 is satisfied, the oil pump 7 is stopped in step S8. After the oil pump 7 is stopped, the monitoring of the motor power amount w per unit time is started again. As described above, when the power amount WT per fixed time T exceeds the threshold value WTH, or the integrated power value When WS exceeds the threshold value WSH, the oil pump 7 is started to perform forced cooling with lubricating oil.

  As described above, in the present embodiment, the power amount w of the motor 3 is monitored every unit time, and the oil pump 7 is stopped and the forced cooling of the motor 3 is stopped until the present time. The timing for forcibly cooling the motor 3 is determined using the integrated value WS of w and the amount of electric power WT during a certain period of time. Thereby, the temperature of the motor 3 can be accurately grasped without a response delay, and the motor 3 can be cooled at an appropriate timing.

DESCRIPTION OF SYMBOLS 1 Vehicle 3 Motor 5 Transmission 7 Oil pump 101 Hybrid control unit 101a Motor power monitoring part 101b Motor cooling determination part 101c Motor cooling control part WS Power integrated value WSH threshold value (2nd threshold value)
WT Electric energy per fixed time WTH threshold (first threshold)
w Motor power per unit time

Claims (3)

In a vehicle-mounted motor cooling device that transfers a cooling medium to a motor mounted on a vehicle via a transfer device to cool the motor,
A motor power monitoring unit that monitors the amount of power supplied to the motor and the amount of power generated by the motor as a motor power amount every predetermined unit time, and integrates the motor power amount;
Based on the integrated value of the motor power amount from the stop of the transfer of the cooling medium to the motor by the transfer device integrated by the motor power monitoring unit to the forced cooling of the motor. A motor cooling determination unit for determining necessity, and
It said motor cooled by an instruction from the determination unit, before the cooling device of the in-vehicle motor, characterized in that a motor cooling control unit that drives the KiUtsuri feeding device forcibly cool the motor. The motor cooling determination unit further performs forced cooling of the motor based on an integrated value of the motor electric energy for a predetermined time after the transfer of the cooling medium to the motor by the transfer device is stopped . The in-vehicle motor cooling device according to claim 1, wherein the necessity is determined.   The cooling medium is lubricating oil and the transfer device is an oil pump, and the motor cooling control unit drives the oil pump to transfer the lubricating oil to the motor and to transfer the lubricating oil to the transmission of the vehicle. The on-vehicle motor cooling device according to claim 1 or 2.