JP7126400B2 - Temperature sensor oil immersion determination device and electric motor control device - Google Patents

Description

The present disclosure provides a temperature sensor oil immersion determination device that performs oil immersion determination for a temperature sensor that detects the temperature of an electric motor mounted in a vehicle, and an electric motor control device that includes such an oil immersion determination device. Regarding.

2. Description of the Related Art In recent years, hybrid electric vehicles (HEVs) have been widely put into practical use, in which an engine and an electric motor are used together to effectively improve the fuel consumption rate (fuel efficiency) of the vehicle. Also, an electric vehicle (EV) that uses only an electric motor as a power source and does not emit exhaust gas has been put to practical use.

In such hybrid vehicles and electric vehicles, a temperature sensor is provided to detect (monitor) the temperature of the electric motor in order to prevent overheating of the electric motor (and thus demagnetization or demagnetization of the permanent magnet due to overheating). (See Patent Document 1, for example).

JP 2012-217303 A

By the way, in such vehicles such as hybrid vehicles and electric vehicles, the temperature sensor for the electric motor may be submerged in predetermined oil depending on the driving conditions of the vehicle. Therefore, it is required to easily determine whether or not such a temperature sensor is immersed in oil (oil immersion determination). It is desirable to provide a temperature sensor oil immersion determination device capable of easily determining oil immersion in a temperature sensor for an electric motor, and an electric motor control device equipped with such an oil immersion determination device. .

A temperature sensor oil immersion determination device according to an embodiment of the present disclosure provides a first temperature sensor for detecting the temperature of an electric motor mounted in a vehicle and cooled by oil. is immersed in oil. This judging section judges whether or not the following conditions (A) and (B) respectively hold when judging oil immersion, and also judges that both conditions (A) and (B) hold. If so, it is determined that the first temperature sensor is submerged in oil.
(A) The acceleration of the vehicle detected by the acceleration sensor is equal to or greater than the first threshold. (B) The temperature of the electric motor detected by the first temperature sensor and the second temperature for detecting the temperature of the oil. The absolute value of the temperature difference from the temperature of the oil detected by the sensor is less than or equal to the second threshold

An electric motor control device according to an embodiment of the present disclosure provides a first temperature sensor for detecting the temperature of an electric motor mounted on a vehicle and cooled by oil. A determination unit that determines whether or not the oil is submerged in oil, and a temperature that estimates the temperature of the electric motor when the determination unit determines that the first temperature sensor is submerged in oil. An estimating unit, and a motor control unit that limits the output of the electric motor based on the temperature of the electric motor detected by the first temperature sensor or the temperature of the electric motor estimated by the temperature estimating unit. is. The judging section judges whether or not the following conditions (A) and (B) respectively hold when judging oil immersion, and also judges that both conditions (A) and (B) hold. If so, it is determined that the first temperature sensor is submerged in oil.
(A) The acceleration of the vehicle detected by the acceleration sensor is equal to or greater than the first threshold. (B) The temperature of the electric motor detected by the first temperature sensor and the second temperature for detecting the temperature of the oil. The absolute value of the temperature difference from the temperature of the oil detected by the sensor is less than or equal to the second threshold

According to the temperature sensor oil immersion determination device and the electric motor control device according to the embodiment of the present disclosure, it is possible to easily perform the oil immersion determination for the temperature sensor for the electric motor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a schematic configuration example of a vehicle including an oil immersion determination device for a temperature sensor according to an embodiment of the present disclosure; FIG. 3 is a schematic diagram for explaining how the temperature sensor shown in FIG. 1 is submerged in oil; It is a schematic diagram for demonstrating the time change of various temperatures. 4 is a flow chart showing an example of a temperature sensor oil immersion determining method and an electric motor output limiting method according to an embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be given in the following order.
1. Embodiment (an example of a method for judging that a temperature sensor is immersed in oil using two conditions)
2. Modification

<1. Embodiment>
[Schematic configuration of vehicle]
FIG. 1 schematically illustrates a schematic configuration example of a vehicle (HEV 1) provided with a temperature sensor oil immersion determination device (HEV-ECU 50 described later) according to an embodiment of the present disclosure. In the present embodiment, an example will be described in which the temperature sensor oil immersion determination device described above is applied to a series-parallel hybrid vehicle. Also, this HEV 1 corresponds to a specific example of "vehicle" in the present disclosure.

As shown in FIG. 1, the HEV 1 mainly includes an engine 10, electric motors (motor generators) 11 and 12, a power split device 13, a drive train 14, an oil pan 30, a mechanical oil pump 32, and an electric oil pump 33. , oil cooler 40, HEV-ECU 50, PCU 60, battery 70 and ECU 80. This HEV 1 also has an acceleration sensor 57 , an outside air temperature sensor 58 , a vehicle speed sensor 59 , a crank angle sensor 81 , an accelerator sensor 82 and a water temperature sensor 83 .

(A. Engine 10)
The engine 10 may be of any type, but for example, an engine designed to improve thermal efficiency by increasing the compression ratio through a high expansion ratio cycle is preferably used. The engine 10 is controlled by an ECU (engine control unit) 80, which will be described later.

The power split device 13, as shown in FIG. 1, is connected to the crankshaft of the engine 10 and has, for example, a planetary gear mechanism composed of a ring gear, a pinion gear, a sun gear and a planetary carrier (not shown). An electric motor 11 to be described later is connected to the power split device 13 . The power split mechanism 13 splits and transmits the driving force generated from the engine 10 to the drive train 14 and the electric motor 11, which will be described later.

The drive train 14 is connected to the power split device 13, as shown in FIG. 1, and is configured using a reduction gear or the like. The drive train 14 is also connected to an electric motor 12 which will be described later.

(B. Electric motors 11, 12)
Each of the electric motors 11 and 12 is an oil-cooled electric motor cooled by an oil 39 to be described later, and is, for example, a three-phase AC type AC synchronous motor. In these electric motors 11 and 12, for example, permanent magnets are used for rotors and coils are used for stators. That is, as shown in FIG. 1, the electric motor 11 is provided with a coil 11a as a stator, and the electric motor 12 is provided with a coil 12a as a stator.

Conversely, coils may be used for the rotors of the electric motors 11 and 12, and permanent magnets may be used for the stators. Also, as the electric motors 11 and 12, for example, an AC induction motor, a DC motor, or the like may be used instead of the AC synchronous motor described above.

The electric motor 11 mainly operates as a generator, and the electric motor 12 mainly operates as a power source of the HEV 1 . Therefore, in this HEV 1, two power sources, the engine 10 and the electric motor 12, can be used to drive the wheels (vehicle). In addition, the HEV 1 can switch between running using only the electric motor 12 as a power source and running using both the engine 10 and the electric motor 12 as power sources depending on, for example, the running conditions. there is Furthermore, the HEV 1 can also generate electricity using the electric motor 11 while traveling using the electric motor 12 as a power source. The engine 10 and the electric motors 11 and 12 are comprehensively controlled by a HEV-ECU (hybrid vehicle control unit) 50, which will be described later.

Here, as shown in FIG. 1, the coil 11a of the electric motor 11 is provided with a temperature sensor 21 for detecting the temperature T1 of (the stator of) the electric motor 11. As shown in FIG. Similarly, the coil 12a of the electric motor 12 is provided with a temperature sensor 22 for detecting the temperature T2 of (the stator of) the electric motor 12 . Each of these temperature sensors 21 and 22 is configured using, for example, a thermistor whose resistance value changes according to temperature. The temperatures T1 and T2 detected by the temperature sensors 21 and 22 are supplied as electric signals (voltage values) corresponding to the temperatures T1 and T2 to the HEV-ECU 50, which will be described later (Fig. 1).

Here, each of these temperature sensors 21 and 22 corresponds to a specific example of "first temperature sensor" in the present disclosure.

(C. Oil pan 30)
Inside the oil pan 30, as shown in FIG. 1, oil 39 is stored and an oil strainer 31 is accommodated. The oil 39 is oil for lubricating and cooling the electric motors 11 and 12 described above, and lubricating the power split mechanism 13 and the drive train 14 described above. The oil strainer 31 is a filter for removing foreign matter contained in this oil 39 .

An oil temperature sensor 23 is provided in the oil pan 30 (or a pipe communicating between the oil strainer 31 and a mechanical oil pump 32 or an electric oil pump 33, which will be described later), as shown in FIG. there is The oil temperature sensor 23 is a sensor that detects the temperature T3 (oil temperature) of the oil 39 stored in the oil pan 30 . Like the temperature sensors 21 and 22 described above, the oil temperature sensor 23 is constructed using, for example, a thermistor whose resistance value changes according to the temperature. The temperature T3 detected by the oil temperature sensor 23 is also supplied to the HEV-ECU 50, which will be described later, as an electric signal (voltage value) corresponding to this temperature T3 (see FIG. 1).

Here, this oil temperature sensor 23 corresponds to a specific example of the "second temperature sensor" in the present disclosure.

(D. Mechanical oil pump 32, electric oil pump 33)
The mechanical oil pump 32 and the electric oil pump 33 are oil pumps for supplying the oil 39 stored in the oil pan 30 to the electric motors 11 and 12, respectively. The mechanical oil pump 32 and the electric oil pump 33 are arranged in parallel with each other as shown in FIG.

A mechanical oil pump (mechanical OP) 32 is a pump driven by the engine 10, sucks up oil 39 stored in the oil pan 30 via an oil strainer 31, pressurizes it, and discharges it. (see Figure 1). Further, the oil 39 discharged in this way is pressure-fed to the oil cooler 40 as shown in FIG. As the mechanical oil pump 32, for example, a coaxial internal gear/trochoid type or a chain driven vane type is preferably used.

The electric oil pump 33 is, for example, a pump driven by an electric motor (not shown) when the engine 10 is stopped. Similarly to the mechanical oil pump 32, the electric oil pump 33 also sucks up the oil 39 stored in the oil pan 30 through the oil strainer 31, pressurizes it, and discharges it ( See Figure 1). Similarly, the oil 39 discharged in this way is also pressure-fed to the oil cooler 40 as shown in FIG. The operation of the electric oil pump 33 is controlled by the HEV-ECU 50, which will be described later.

(E. Oil cooler 40)
The oil cooler 40 is provided on the downstream side of the mechanical oil pump 32 and the electric oil pump 33 described above. It is designed to cool the oil 39 . In the example shown in FIG. 1, the oil cooler 40 is an air-cooled oil cooler that exchanges heat between the oil 39 and the outside air (cooling medium). Instead of such an air-cooled oil cooler, for example, a water-cooled oil cooler that exchanges heat between the oil 39 and cooling water (cooling medium) such as engine cooling water is used as the oil cooler 40. may be used.

(F.HEV-ECU50)
The HEV-ECU 50 comprehensively controls the operations of the engine 10 and the electric motors 11 and 12 based on various information. The HEV-ECU 50 includes a microprocessor that performs calculations, a ROM (Read Only Memory) that stores programs and the like for causing the microprocessor to execute various processes, and a RAM (Random Access Memory) that stores various data such as calculation results. , a backup RAM for holding the stored contents, an input/output I/F (Interface), and the like.

Here, the HEV-ECU 50 is connected via a CAN (Controller Area Network) 100 to an ECU 80, which will be described later, a vehicle dynamic control unit (VDCU) (not shown), etc., so as to be able to communicate with each other. The HEV-ECU 50 receives various types of information (eg, engine speed, cooling water temperature, accelerator pedal opening, etc.) from the ECU 80 and VDCU via the CAN 100 . The HEV-ECU 50 comprehensively controls the operations of the engine 10 and the electric motors 11 and 12, as described above, based on the acquired various information.

As shown in FIG. 1, the HEV-ECU 50 includes an oil immersion determining unit 51, a pump discharge amount obtaining unit 52, an operating state obtaining unit 53, an oil temperature estimating unit 54, a motor temperature estimating unit 55, and a motor control unit. 56. Various sensors such as an acceleration sensor 57, an outside air temperature sensor 58, and a vehicle speed sensor 59 are connected to the HEV-ECU 50, as shown in FIG.

The acceleration sensor 57 is a sensor that detects the acceleration a of the HEV1. The outside air temperature sensor 58 is a sensor that detects the outside air temperature of the HEV 1 (outside air temperature). A vehicle speed sensor 59 is a sensor that detects the speed of the HEV 1 (vehicle speed).

The HEV-ECU 50 as described above corresponds to a specific example of a "temperature sensor oil immersion determination device" and an "electric motor control device" in the present disclosure.

(F-1. Oil immersion determination unit 51)
Although details will be described later (FIG. 2), the oil immersion determination unit 51 determines whether or not the temperature sensors 21 and 22 are immersed in the oil 39 (oil immersion). judgment). Specifically, the oil immersion determination unit 51 determines whether or not the following conditions (A) and (B) are respectively satisfied at the time of such oil immersion determination, thereby determining whether the temperature sensors 21 and 22 is submerged in the oil 39.
(A) The acceleration a of the HEV 1 detected by the acceleration sensor 57 is equal to or greater than the threshold acceleration ath (a≧ath). (B) The temperature T1 of the electric motor 11 detected by the temperature sensor 21 (or the temperature sensor 22 The absolute value of the temperature difference (|T1-T3| or |T2-T3|) between the temperature T2 of the electric motor 12 detected by the oil temperature sensor 23 and the temperature T3 of the oil 39 detected by the oil temperature sensor 23 is the threshold temperature Difference ΔTth or less (|T1-T3|≦ΔTth or |T2-T3|≦ΔTth)

Note that (|T1-T3|≤ΔTth or |T2-T3|≤ΔTth) in the above condition (B) is hereinafter expressed as (|(T1, T2)-T3|≤ΔTth) for convenience. (see FIG. 4 and the like, which will be described later).

Here, when it is determined that both of the above conditions (A) and (B) are satisfied, the oil immersion determination unit 51 determines that the temperature sensors 21 and 22 are immersed in the oil 39 . On the other hand, when it is determined that at least one of the above conditions (A) and (B) is not established, the oil immersion determination unit 51 determines that the temperature sensors 21 and 22 are not immersed in the oil 39. It's like Details of such oil immersion determination (oil immersion determination processing) will be described later (FIGS. 2 to 4).

Note that such an oil immersion determination unit 51 corresponds to a specific example of the "determination unit" in the present disclosure. Further, the threshold acceleration ath (for example, 0.7 (G)) described above corresponds to a specific example of the "first threshold" in the present disclosure. Furthermore, the above threshold temperature difference ΔTth (for example, about 3% of the temperature detected by the oil temperature sensor 23) corresponds to a specific example of the "second threshold" in the present disclosure.

(F-2. Pump Discharge Amount Acquisition Unit 52)
The pump discharge amount obtaining unit 52 obtains the oil discharge amounts of the mechanical oil pump 32 and the electric oil pump 33 described above.

Specifically, the pump discharge amount acquisition unit 52 first obtains the rotation speed (pump rotation speed) of the mechanical oil pump 32 based on the engine rotation speed and gear ratio of the mechanical oil pump 32 . Then, the pump discharge amount acquisition unit 52 obtains the oil discharge amount of the mechanical oil pump 32 based on the pump rotation speed thus obtained. The discharge amount of the mechanical oil pump 32 may be obtained based on, for example, the speed of the HEV 1 instead of the engine speed described above.

Further, the pump discharge amount acquisition unit 52 obtains the discharge amount of the electric oil pump 33 based on the duty of the voltage applied to the electric oil pump 33 .

The discharge amounts of the mechanical oil pump 32 and the electric oil pump 33 obtained by the pump discharge amount acquisition unit 52 in this manner are output to the oil temperature estimation unit 54, which will be described later. .

(F-3. Operating state acquisition unit 53)
The operating state acquisition unit 53 acquires the operating state (for example, output torque, motor rotation speed, etc.) of each of the electric motors 11 and 12 . The operating state information obtained by the operating state obtaining unit 53 in this manner is output to the motor temperature estimating unit 55, which will be described later.

(F-4. Oil temperature estimation unit 54)
When the oil immersion determination unit 51 determines that the temperature sensors 21 and 22 are immersed in the oil 39, the oil temperature estimation unit 54 calculates the temperature of the oil 39 (after passing through the oil cooler 40). temperature of the oil 39).

Specifically, the oil temperature estimator 54 first determines the flow rate of the oil cooler 40 based on the discharge amounts of the mechanical oil pump 32 and the electric oil pump 33 output from the pump discharge amount acquisition unit 52 described above. Find the amount of oil. The amount of oil passing through the oil cooler 40 is preferably determined in consideration of the pressure loss ratio of the circuit. Next, the oil temperature estimator 54 determines the temperature of the oil 39 stored in the oil pan 30, the amount of oil passing through the oil cooler 40, the temperature of the cooling medium in the oil cooler 40 (for example, the outside air temperature The temperature of the oil 39 after passing through the oil cooler 40 is estimated based on the outside air temperature detected by the sensor 58 and the speed of the HEV 1 (vehicle speed) detected by the vehicle speed sensor 59 . That is, the oil temperature estimator 54 estimates the temperature of the oil 39 supplied to the electric motors 11 and 12 . The temperature of the oil 39 estimated by the oil temperature estimating section 54 in this manner is output to the motor temperature estimating section 55, which will be described later.

In the above description, an example in which the oil cooler 40 is of an air-cooled type has been described. That is, the oil temperature estimator 54 calculates the temperature of the oil 39 stored in the oil pan 30, the discharge amounts of the mechanical oil pump 32 and the electric oil pump 33, and the cooling medium in the oil cooler 40. The temperature of the oil 39 after passing through the oil cooler 40 is estimated based on the temperature (the temperature of the cooling water).

(F-5. Motor temperature estimator 55)
The motor temperature estimating unit 55 determines the temperatures (temperatures T1, T2) of the electric motors 11, 12 when the oil immersion determining unit 51 determines that the temperature sensors 21, 22 are immersed in the oil 39. is estimated.

Specifically, the motor temperature estimating unit 55 uses the operating state (output torque, motor rotation speed, etc.) of each of the electric motors 11 and 12 output from the operating state acquiring unit 53 and the estimated oil temperature. Temperatures T1 and T2 of electric motors 11 and 12 are calculated based on the temperature (estimated temperature) of oil 39 output from unit 54 and the flow rate (oil flow rate) of oil 39 in each of electric motors 11 and 12. presume. The temperatures T1 and T2 of the electric motors 11 and 12 estimated by the motor temperature estimating section 55 in this manner are output to the motor control section 56, which will be described later.

Here, such a motor temperature estimator 55 corresponds to a specific example of the "temperature estimator" in the present disclosure.

(F-6. Motor control unit 56)
The motor control unit 56 limits the output of each of the electric motors 11 and 12 by setting, for example, a torque command value for each of the electric motors 11 and 12 based on various information (performs motor output limitation processing). It is.

Specifically, the motor control unit 56 controls, for example, the accelerator pedal opening detected by the accelerator sensor 82 (described later) (request of the driver of the HEV 1), the operating state of the HEV 1, and the state of charge of the battery 70 (described later). Such motor output limitation processing is performed based on various information such as SOC (State Of Charge).

At that time, the motor control unit 56 performs motor output restriction processing in the electric motors 11 and 12 according to the detected or estimated temperatures (temperatures T1 and T2) of the electric motors 11 and 12 . Specifically, the motor control unit 56 controls the temperatures T1 and T2 of the electric motors 11 and 12 detected by the temperature sensors 21 and 22, or the temperatures T1 and T2 of the electric motors 11 and 12 estimated by the motor temperature estimation unit 55 described above. The outputs of the electric motors 11, 12 are restricted based on the temperatures T1, T2. More specifically, when the temperatures T1 and T2 of the electric motors 11 and 12 thus detected or estimated are equal to or higher than the threshold temperature Tth ((T1, T2)≧Tth), the motor control unit 56 limits the outputs (for example, torque command values) of the electric motors 11 and 12 so that the output upper limits of the electric motors 11 and 12 are relatively low. The details of such motor output restriction processing will be described later (FIG. 4).

Here, the threshold temperature Tth described above corresponds to a specific example of the "third threshold" in the present disclosure.

(G. PCU 60, battery 70)
Battery 70 is a battery that stores DC power. A PCU (power control unit) 60 is connected to the battery 70 as shown in FIG.

The PCU 60 drives the electric motors 11 and 12, respectively, and has an inverter 61 and a DC-DC converter 62 as shown in FIG. Specifically, the PCU 60 drives the electric motors 11 and 12 via the inverter 61 based on the torque command value (set in the motor control unit 56) output from the HEV-ECU 50. It is designed to

The inverter 61 converts the DC power stored in the battery 70 into three-phase AC power (AC power), and supplies the AC power to the electric motors 11 and 12, respectively. The inverter 61 also converts the AC power generated by the electric motors 11 and 12 into DC power and charges the battery 70 with the DC power.

The DC-DC converter 62 steps down the DC voltage (high DC voltage) stored in the battery 70 and outputs it as a low DC voltage. The DC low voltage generated in this manner is supplied to, for example, accessories (not shown), the HEV-ECU 50, and an ECU 80 to be described later.

(H.ECU 80)
Various sensors such as a crank angle sensor 81, an accelerator sensor 82 and a water temperature sensor 83 are connected to the ECU 80 as shown in FIG.

The crank angle sensor 81 is a sensor that detects the rotational position (engine speed) of a crankshaft (not shown) in the engine 10 . The accelerator sensor 82 is a sensor that detects the aforementioned accelerator pedal opening (the amount of depression of the accelerator pedal by the driver of the HEV 1). The water temperature sensor 83 is a sensor that detects the temperature of cooling water (cooling water temperature) in the engine 10 .

Based on various information detected by these various sensors and control information from the HEV-ECU 50, the ECU 80 controls various devices such as fuel injection amount, ignition timing, and electronically controlled throttle valve. By controlling, the engine 10 is controlled. Further, the ECU 80 supplies the above-described various information (engine speed, accelerator pedal opening, cooling water temperature, etc.) to the HEV-ECU 50 via the CAN 100 .

[Operation and action/effect]
Next, the operation, functions and effects of the HEV 1 of this embodiment will be described.

(A. Submergence of Temperature Sensors 21 and 22 in Oil)
First, with reference to FIGS. 2 and 3, oil immersion of temperature sensors 21 and 22 for detecting temperatures T1 and T2 of electric motors 11 and 12, respectively, will be described. FIG. 2 schematically shows how these temperature sensors 21 and 22 are immersed in oil. Moreover, FIG. 3 schematically shows changes over time of various temperatures (temperatures T1, T2, T3, etc. described above). Note that the actual temperature T0 shown in FIG. 3 represents the actual temperature of the electric motors 11 and 12 (not the values of the temperatures T1 and T2 detected by the temperature sensors 21 and 22, but the actual temperature values). .

First, in the schematic structure (partial schematic structure of the transmission 90) shown in FIG. stationary oil surface) is the oil surface along the horizontal direction. 2, the temperature sensors 21 and 22 provided in the electric motors 11 and 12 are set to be positioned above the oil level Lo1 when traveling on a flat road or the like. , so as not to be submerged in the oil 39 .

However, when the HEV 1 climbs a hill or accelerates, the oil level Lo2 of the oil 39 transitionally tilts from the horizontal direction (oil level Lo1), as indicated by an arrow P1 in FIG. 2, for example. (See the oil immersion angle θ in FIG. 2). When such a transient oil level change occurs in the oil 39, the temperature sensors 21 provided in the electric motors 11 and 12 may , 22 are each immersed in the oil 39 .

Here, when the temperature sensors 21 and 22 are submerged in the oil 39 in this way, the protection control for the electric motors 11 and 12 can be properly executed as shown in FIG. 3, for example. There is a possibility that the electric motors 11 and 12 may be damaged.

Specifically, first, the temperature sensors 21 and 22 are not submerged in the oil 39 as described above during the period from timing t0 to t1 in FIG. Accordingly, the temperatures T1 and T2 detected by these temperature sensors 21 and 22 substantially match the actual temperature T0 of the electric motors 11 and 12 (see FIG. 3). In other words, the temperature sensors 21 and 22 can correctly detect the temperatures T1 and T2 of the electric motors 11 and 12 during the period from timing t0 to t1.

On the other hand, for example, in a period after timing t1 in FIG. 39 is submerged in oil, it will be as follows. That is, for example, as indicated by an arrow P2 in FIG. It almost coincides with T3. In other words, in this case, the temperature sensors 21 and 22 cannot correctly detect the temperatures T1 and T2 of the electric motors 11 and 12 (actually, the temperature T3 of the oil 39 is detected).

Then, for example, in a period after timing t2 in FIG. 3, the actual temperature T0 of the electric motors 11 and 12 exceeds a predetermined threshold temperature Tth (threshold for executing protective control on the electric motors 11 and 12). Nevertheless, such protective control is no longer executed. That is, the temperatures T1 and T2 (temperature T3 of the oil 39) detected by the electric motors 11 and 12 do not exceed the threshold temperature Tth (see FIG. 3). and the electric motors 11 and 12 may be damaged.

In addition, as a solution to such a problem, for example, the following can be considered. That is, first, there is a method of changing the arrangement positions of the temperature sensors 21 and 22 to positions where they are not immersed in the oil even when the oil level of the oil 39 changes transiently. Further, in addition to the current temperature sensors 21 and 22, there is a method of separately adding parts such as a new temperature sensor at a position where the oil 39 is not submerged even by a transient oil level change. However, if the arrangement positions of the temperature sensors 21 and 22 are changed or new parts (another temperature sensor, etc.) are added in this way, the cost will be increased due to the restrictions on the parts layout and the addition of parts. It may increase.

(B. Method for judging oil immersion in the present embodiment, etc.)
Therefore, in the present embodiment, the oil immersion determination unit 51 in the HEV-ECU 50 performs the oil immersion determination for the temperature sensors 21 and 22 using a technique described in detail below. In addition, the motor control unit 56 in the HEV-ECU 50 limits the outputs of the electric motors 11 and 12 using a method described in detail below.

Hereinafter, with reference to FIG. 4 in addition to FIGS. 1 to 3, an example of a method for determining oil immersion in temperature sensors 21 and 22 and a method for limiting output of electric motors 11 and 12 according to the present embodiment will be described in detail. do. FIG. 4 is a flowchart showing an example of such an oil immersion determination method (oil immersion determination process) and an output restriction method (motor output restriction process). Note that the series of processes shown in FIG. 4 are mainly repeatedly executed by the HEV-ECU 50 at predetermined timings.

(B-1. Oil immersion determination process: S101 to S104)
In the series of processes shown in FIG. 4, the oil immersion determination section 51 in the HEV-ECU 50 first performs an oil immersion determination process, which will be described in detail below (steps S101 to S104 in FIG. 4).

Specifically, the oil immersion determination unit 51 first determines whether or not the above-described condition (A) is established (whether or not a≧ath is satisfied) (step S101). Note that this condition (A) corresponds to the determination process for estimating the inclination state (oil immersion angle θ) of the oil surface of the oil 39 described above in FIG.

Here, when it is determined that the condition (A) is satisfied (a≧ath is satisfied) (step S101: Y), the oil immersion determination unit 51 determines the oil immersion angle θ (inclination state of the oil surface) is out of the allowable range, and then the process proceeds to step S102, which will be described later.

On the other hand, when it is determined that the condition (A) is not established (a≧ath is not satisfied) (step S101: N), the oil immersion determination unit 51 determines the oil immersion angle θ (inclination state of the oil surface) is within the allowable range, and it is determined that the temperature sensors 21 and 22 are not submerged in the oil 39 (step S103). In addition, after that, it will progress to step S105 mentioned later.

Here, in step S102 described above, the oil immersion determination unit 51 determines whether or not the above-described condition (B) is further established (whether |(T1, T2)−T3|≦Tth is satisfied). do. 2, the temperature sensors 21 and 22 cannot correctly detect the temperatures T1 and T2 of the electric motors 11 and 12 (actually, the temperature T3 of the oil 39 is It corresponds to the determination process of estimating whether there is a risk of detection.

Here, if it is determined that the condition (B) is not established (|(T1, T2)−T3|≦Tth is not satisfied) (step S102: N), the process is as follows. That is, the oil immersion determination unit 51 estimates that there is no possibility that the temperatures T1 and T2 are not correctly detected, and determines that the temperature sensors 21 and 22 are not immersed in the oil 39 (step S103). In addition, after that, it will progress to step S105 mentioned later.

On the other hand, if it is determined that the condition (B) is satisfied (|(T1, T2)-T3|≤Tth) (step S102: Y), both the conditions (A) and (B) are satisfied. Since it will be established, it will be as follows. That is, the oil immersion determination unit 51 estimates that the temperatures T1 and T2 may not be detected correctly, and determines that the temperature sensors 21 and 22 are immersed in the oil 39 (step S104). In addition, after that, it will progress to step S106 mentioned later.

(B-2. Estimation process of temperature of electric motors 11 and 12, etc.: S105 to S107)
Subsequently, in step S105 described above, the base temperature Tmb of the electric motors 11 and 12 is set according to the temperatures T1 and T2 detected by the temperature sensors 21 and 22, respectively. In addition, after that, it will progress to step S107 mentioned later.

On the other hand, in step S106 described above, the HEV-ECU 50 (motor temperature estimator 55, etc.) performs various calculations described below to estimate the temperatures T1 and T2 of the electric motors 11 and 12. FIG. In addition, after that, it will progress to step S107 demonstrated below.

In step S107, the motor control unit 56 in the HEV-ECU 50 determines whether the temperatures T1 and T2 of the electric motors 11 and 12 thus detected or estimated are equal to or higher than the threshold temperature Tth ( (T1, T2)≧Tth) is determined. That is, the motor control unit 56 makes such a determination based on the temperatures T1 and T2 detected by the temperature sensors 21 and 22 or the temperatures T1 and T2 estimated in step S106 described above.

Here, if it is determined that (T1, T2)≧Tth is not satisfied (step S107: N), the process proceeds to step S108, which will be described later. On the other hand, if it is determined that (T1, T2)≧Tth is satisfied (step S107: Y), the process proceeds to step S109, which will be described later.

Here, the process of estimating the temperatures T1 and T2 of the electric motors 11 and 12 (step S106) is as follows.

That is, in the process of estimating the temperatures T1 and T2, first, the oil temperature estimating unit 54 calculates the respective discharge values of the mechanical oil pump 32 and the electric oil pump 33, which are output from the pump discharge amount acquiring unit 52 as described above. Based on the amount and the like, the temperature of the oil 39 after passing through the oil cooler 40 (the temperature of the oil 39 supplied to the electric motors 11 and 12) is estimated. Then, the motor temperature estimating unit 55 calculates the operation state (output torque, motor rotation speed, etc.) of each of the electric motors 11 and 12 output from the operating state acquisition unit 53 as described above, and the oil temperature estimation described above. Based on the temperature of the oil 39 estimated in the unit 54 and the flow rate of the oil 39 in each of the electric motors 11 and 12 (oil flow rate), the temperatures T1 and T2 of the electric motors 11 and 12 are estimated.

(B-3. Motor Output Limiting Process: S108 to S110)
Subsequently, the motor control unit 56 performs processing (motor output limiting processing) for limiting the outputs of the electric motors 11 and 12 as follows (steps S108 to S110).

First, if it is determined that (T1, T2)≧Tth is not satisfied as described above (step S107: N), then the motor control unit 56 sets the output upper limit value Pmax1 of the electric motors 11 and 12. (Step S108). On the other hand, if it is determined that (T1, T2)≧Tth is satisfied (step S107: Y), then the motor control unit 56 sets the output upper limit value Pmax2 of the electric motors 11 and 12 (step S109).

Here, the output upper limit value Pmax2 is a value relatively lower than the output upper limit value Pmax1 (Pmax2<Pmax1). That is, when the temperatures T1 and T2 of the electric motors 11 and 12 are equal to or higher than the threshold temperature Tth, the output upper limit values of the electric motors 11 and 12 are set relatively low.

Subsequently, the motor control unit 56 determines the target rotation speed, target torque, and torque command value of the electric motors 11 and 12 as follows, taking into account the output upper limit values Pmax1 and Pmax2 thus set. Each is set (step S110).

Specifically, first, the motor control unit 56 sets the required rotation speed and the required torque of the electric motors 11 and 12, respectively, according to the accelerator pedal opening, for example. Next, the motor control unit 56 sets the target rotation speed and the target torque of the electric motors 11 and 12 according to the required rotation speed and the required torque thus set. Then, the motor control unit 56 sets torque command values for the electric motors 11 and 12 according to the target rotation speed and target torque set in this way.

Subsequently, the motor control unit 56 performs calculations so that the torque command value thus set satisfies the output upper limit value Pmax1 set in step S108 or the output upper limit value Pmax2 set in step S109. to calculate the temporary motor torque. Next, the motor control unit 56 sets the final torque command value according to the temporary motor torque calculated in this way.

The target rotation speed, target torque and torque command value for electric motors 11 and 12 set in this way are respectively output from HEV-ECU 50 (motor control unit 56) to PCU 60. FIG. Then, the PCU 60 drives the electric motors 11 and 12 based on these target rotation speed, target torque and torque command value. This completes the description of the series of processes shown in FIG.

(C. action and effect)
As described above, in the present embodiment, HEV-ECU 50 (oil immersion determination unit 51) performs the following operation when determining temperature sensors 21 and 22 for detecting temperatures of electric motors 11 and 12 to be immersed in oil. to make a decision. That is, the HEV-ECU 50 determines that the temperature sensors 21 and 22 are submerged in the oil 39 when it is determined that both the conditions (A) and (B) described above are satisfied.

As a result, in the present embodiment, the temperature sensors 21 and 22 can be installed without changing the arrangement positions of the temperature sensors 21 and 22 or adding new parts (another temperature sensor or the like) as described above. Oil immersion determination is realized. That is, it is possible to perform such an oil immersion determination simply by changing the processing in the HEV-ECU 50 while adopting the structure of the existing HEV as it is. Therefore, in the present embodiment, it is possible to easily determine whether the temperature sensors 21 and 22 for the electric motors 11 and 12 are out of oil. In addition, since it is not necessary to change the positions of the temperature sensors 21 and 22 or add new parts, it is possible to reduce the cost.

Further, the HEV-ECU 50 (oil immersion determination unit 51) determines that the temperature sensors 21 and 22 are immersed in the oil 39 when it is determined that at least one of the conditions (A) and (B) described above is not satisfied. Since it is determined that it is not, it will be as follows. That is, it is possible to easily determine whether the temperature sensors 21 and 22 are not submerged in oil while adopting the structure of the existing HEV as it is.

Furthermore, since the HEV-ECU 50 is provided with the motor temperature estimating section 55 and the motor control section 56 and the like, the operation is as follows. That is, even if the temperature sensors 21 and 22 are determined to be submerged in the oil 39 by the oil immersion determination unit 51, the operation of the electric motors 11 and 12 (driving force output operation, power generation operation, etc.) can be maintained (fault tolerance is adopted), and the electric motors 11 and 12 can be protected.

In addition, HEV-ECU 50 (motor control unit 56) controls electric motors 11 and 12 when temperatures T1 and T2 of electric motors 11 and 12 detected or estimated as described above are equal to or higher than threshold temperature Tth. Since the output of the electric motors 11 and 12 is restricted so that the output upper limit value of is relatively low, the following is the case. That is, the electric motors 11 and 12 can be protected more appropriately because the motor output limiting process is realized according to the level of the detected or estimated temperatures T1 and T2.

Further, in the present embodiment, the HEV-ECU 50 performs the following various calculations during the process of estimating the temperatures T1 and T2 of the electric motors 11 and 12 (step S106 in FIG. 4). Therefore, for example, it is possible to obtain the following various effects.

That is, first, based on the engine speed of the mechanical oil pump 32, the rotation speed of the mechanical oil pump 32 (pump rotation speed) is obtained. Discharge volume is required. As a result, the oil discharge amount of the mechanical oil pump 32 can be obtained accurately.

Further, the temperature of the oil 39 after passing through the oil cooler 40 is estimated in consideration of the discharge amount of the electric oil pump 33 . As a result, even when an electric oil pump 33 is provided in addition to the mechanical oil pump 32, for example, as shown in FIG. The temperature of the oil 39 after passing through 40 can be accurately estimated.

Furthermore, based on the temperature of the oil 39 stored in the oil pan 30, the discharge amounts of the mechanical oil pump 32 and the electric oil pump 33, the outside air temperature and the speed of the HEV 1 (vehicle speed), the oil cooler The temperature of oil 39 after passing through 40 is estimated. As a result, for example, when an air-cooled oil cooler 40 is used, the temperature of the oil 39 after passing through the oil cooler 40 can be accurately estimated.

<2. Variation>
Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to these embodiments, and various modifications are possible.

For example, the configuration (type, shape, arrangement, number, etc.) of each member in the HEV 1 is not limited to that described in the above embodiment. That is, the configuration of each of these members may be of other types, shapes, arrangements, numbers, and the like. Further, the values, ranges, magnitude relationships, etc. of the various parameters described in the above embodiments are not limited to those described in the above embodiments, and may be other values, ranges, magnitude relationships, and the like.

Specifically, for example, in the above-described embodiment, a case in which two electric motors (electric motors 11 and 12) are provided in the HEV 1 has been described as an example, but the present invention is not limited to this example. That is, the HEV 1 may include, for example, only one electric motor, or may include, for example, three or more electric motors. In the above embodiment, the two temperature sensors 21 and 22 are both subjected to the above-described oil immersion determination process, motor output restriction process, temperature estimation process, etc. (see FIG. 4). However, it is not limited to this example. That is, depending on the case, for example, only one temperature sensor out of the two temperature sensors 21 and 22 may be the object of the oil immersion determination process, the motor output limit process, the temperature estimation process, and the like. .

In addition, in the above-described embodiment, specific examples of the oil immersion determination process, the motor output limit process, the temperature estimation process, etc. (see FIG. 4) have been described, but the present invention is not limited to these specific examples. . That is, other methods may be used to perform these oil immersion determination processing, motor output restriction processing, temperature estimation processing, and the like.

Furthermore, in the above embodiment, the case where the "temperature sensor oil immersion determination device" and the "electric motor control device" in the present disclosure are applied to a series parallel hybrid vehicle has been described as an example. It is not limited to this example. That is, the "temperature sensor oil immersion determination device" and the "electric motor control device" in the present disclosure can be applied to different types of hybrid vehicles (eg, series hybrid vehicles, parallel hybrid vehicles, etc.). is possible. In addition, the “temperature sensor oil immersion determination device” and the “electric motor control device” in the present disclosure are not limited to hybrid vehicles, but are, for example, electric vehicles (EV) and fuel cell vehicles (FCV). etc. can also be applied.

In addition, the series of processes described in the above embodiments may be performed by hardware (circuit) or by software (program). When it is performed by software, the software consists of a program group for executing each function by a computer. Each program, for example, may be installed in the computer in advance and used, or may be installed in the computer from a network or a recording medium and used.

Also, the various examples described so far may be applied in any combination.

Note that the effects described in this specification are merely examples and are not limited, and other effects may be provided.

Reference Signs List 1 HEV 10 Engine 100 CAN 11, 12 Electric motor 11a, 12a Coil 13 Power split device 14 Drive train 21, 22 Temperature sensor 23 Oil temperature sensor 30 ... Oil pan 31 ... Oil strainer 32 ... Mechanical oil pump 33 ... Electric oil pump 40 ... Oil cooler 50 ... HEV-ECU 51 ... Oil immersion determination unit 52 ... Pump discharge amount acquisition unit 53 ... Operating state acquiring unit 54 Oil temperature estimating unit 55 Motor temperature estimating unit 56 Motor control unit 57 Acceleration sensor 58 Outside air temperature sensor 59 Vehicle speed sensor 60 PCU 61 Inverter 62 DC-DC converter 70 Battery 80 ECU 81 Crank angle sensor 82 Accelerator sensor 83 Water temperature sensor 90 Transmission T0 Actual temperature T1, T2, T3 Temperature Tth Threshold Temperature ΔTth Threshold temperature difference Tmb Base temperature a Acceleration ath Threshold acceleration Lo1, Lo2 Oil level θ Oil immersion angle t Time t0, t1, t2 Timing Pmax1, Pmax2 … Output upper limit value.

Claims (4)

An oil immersion determination is made as to whether or not the first temperature sensor is immersed in the oil with respect to a first temperature sensor that detects the temperature of the electric motor that is mounted on the vehicle and is cooled by oil. Equipped with a judgment unit,
The determination unit is
At the time of the oil immersion determination, it is determined whether the following conditions (A) and (B) are respectively established,
When it is determined that both of the conditions (A) and (B) are established, it is determined that the first temperature sensor is submerged in the oil.
(A) the acceleration of the vehicle detected by the acceleration sensor is equal to or greater than a first threshold; (B) the temperature of the electric motor and the temperature of the oil detected by the first temperature sensor are detected; The absolute value of the temperature difference between the temperature of the oil detected by the second temperature sensor is equal to or less than a second threshold The determination unit determines that the first temperature sensor is not submerged in the oil when it is determined that at least one of the conditions (A) and (B) is not satisfied. An oil immersion determination device for the temperature sensor described above. An oil immersion determination is made as to whether or not the first temperature sensor is immersed in the oil with respect to a first temperature sensor that detects the temperature of the electric motor that is mounted on the vehicle and is cooled by oil. a determination unit;
a temperature estimation unit that estimates the temperature of the electric motor when the determination unit determines that the first temperature sensor is submerged in the oil;
a motor control unit that limits the output of the electric motor based on the temperature of the electric motor detected by the first temperature sensor or the temperature of the electric motor estimated by the temperature estimating unit;
The determination unit is
At the time of the oil immersion determination, it is determined whether the following conditions (A) and (B) are respectively established,
If it is determined that both of the conditions (A) and (B) are satisfied, it is determined that the first temperature sensor is submerged in the oil. An electric motor control device.
(A) the acceleration of the vehicle detected by the acceleration sensor is equal to or greater than a first threshold; (B) the temperature of the electric motor and the temperature of the oil detected by the first temperature sensor are detected; The absolute value of the temperature difference between the temperature of the oil detected by the second temperature sensor is equal to or less than a second threshold The motor control unit
When the temperature of the electric motor detected by the first temperature sensor or the temperature of the electric motor estimated by the temperature estimator is equal to or higher than a third threshold,
4. The electric motor control device according to claim 3, wherein the output of the electric motor is restricted such that the output upper limit value of the electric motor is relatively low.

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