WO2024062555A1

WO2024062555A1 - Failure determination device for transaxle oil temperature sensor

Info

Publication number: WO2024062555A1
Application number: PCT/JP2022/035179
Authority: WO
Inventors: 良小笠原; 佐藤　英信; 徹三浦
Original assignee: 三菱自動車工業株式会社
Priority date: 2022-09-21
Filing date: 2022-09-21
Publication date: 2024-03-28
Also published as: JP7428295B1

Abstract

A failure determination device for a T/A oil temperature sensor 30 that detects the oil temperature of a transaxle 7 of a vehicle 1 includes a failure determination unit 31 that determines a failure of the T/A oil temperature sensor 30 on the basis of the oil temperature of the transaxle 7 from the start of the vehicle 1 until a predetermined running condition is established. The failure determination unit 31 makes a first determination to determine that the difference between the oil temperature of the transaxle 7 at the start of the vehicle 1 and the oil temperature of the transaxle 7 when the predetermined running condition is established is less than a first threshold value, and a second determination to determine that an integrated value of the absolute value of the amount of change in the oil temperature of the transaxle 7 per unit time from the start of the vehicle until when the predetermined running condition is established is less than a second threshold value, and where both the first determination and the second determination are satisfied, it is determined that the T/A oil temperature sensor 30 is stuck abnormally.

Description

Transaxle oil temperature sensor failure determination device

The present invention relates to a technology for determining failure of an oil temperature sensor that detects oil temperature in a vehicle transaxle.

A transaxle included in a vehicle's drive system is filled with lubricating oil (hydraulic oil). Since the operating characteristics of a transmission change depending on the viscosity of the lubricating oil contained therein, it is necessary to accurately detect the temperature of the lubricating oil. The temperature of lubricating oil is generally detected by a temperature sensor.
A common failure of an oil temperature sensor (temperature sensor) is, for example, a stuck state in which the oil temperature sensor outputs a constant temperature even though the oil temperature has changed.

Patent Document 1 describes a failure determination device for an oil temperature sensor of an automatic transmission. Patent Document 1 describes a determination device that determines that an oil temperature sensor is malfunctioning when the oil temperature of an automatic transmission does not rise even if the vehicle travels at a predetermined vehicle speed or higher for a predetermined time.

Japanese Patent Application Publication No. 9-329222

However, depending on changes in temperature, etc. and changes in vehicle speed from the start of driving, the transaxle oil temperature at the start of driving and the oil temperature after driving for a predetermined period of time may be approximately the same, and the oil temperature sensor (transaxle oil temperature sensor) may be incorrectly determined to be malfunctioning.
The present invention has been made to solve these problems, and its purpose is to provide a failure determination device for a transaxle oil temperature sensor that can accurately determine failure.

In order to achieve the above object, the transaxle oil temperature sensor failure determination device of the present invention is provided in a vehicle equipped with a transaxle that transmits power between a drive device that outputs power and a drive shaft. A failure determination device for a transaxle oil temperature sensor that detects the oil temperature of a transaxle, the device detecting a failure of the transaxle oil temperature sensor based on the oil temperature of the transaxle from the time of starting the vehicle until the establishment of a predetermined driving condition. The failure determining section is configured to determine whether the difference between the oil temperature of the transaxle at the time of starting the vehicle and the oil temperature of the transaxle when the driving condition is satisfied is a predetermined first value. a first determination to determine that the temperature is less than a threshold; and a second threshold in which an integrated value of an absolute value of an amount of change in the oil temperature of the transaxle per unit time from the start to the time the driving condition is satisfied is a predetermined second threshold. A second determination is made to determine that the transaxle oil temperature sensor is less than the first determination, and if both the first determination and the second determination are satisfied, it is determined that the transaxle oil temperature sensor is malfunctioning.
Thereby, it can be generally determined by the first determination that the transaxle oil temperature sensor is stuck. However, if the oil temperature of the transaxle rises and falls between the time the vehicle is started and the running conditions are met, and the oil temperature at the transaxle is approximately the same at startup and when the running conditions are met, the second decision will be made even if the first determination is met. is not established and a failure is not determined. Therefore, it is possible to avoid determining that a normal transaxle oil temperature sensor has failed.

Preferably, the running condition is such that the cumulative time during which the running speed of the vehicle is at least a predetermined speed since the start is at least a predetermined time.
As a result, even if the running speed of the vehicle temporarily falls below a predetermined speed before the running conditions are met, the running conditions can be quickly met by increasing the vehicle speed to the predetermined speed or higher, and the transaxle oil It is possible to shorten the time required for determining a failure of the temperature sensor.

Preferably, the vehicle includes a generator disposed adjacent to the transaxle, and a generator oil temperature detection section that detects an oil temperature of the generator, and the failure determination section is configured to detect the It is preferable to perform a failure determination of the transaxle oil temperature sensor when the oil temperature of the generator is below a predetermined third threshold value.
As a result, the oil temperature of the transaxle and the oil temperature of the generator adjacent to the transaxle have similar oil temperature movements, so the oil temperature of the generator at the time of startup is a prerequisite for determining the failure of the transaxle oil temperature sensor. The reliability of failure determination is improved by performing failure determination of the transaxle oil temperature sensor in an environment where a large change in generator oil temperature can be ensured from the time of startup until the predetermined running conditions are met. can be done.

Preferably, the vehicle includes a generator disposed adjacent to the transaxle, and a generator oil temperature detection section that detects an oil temperature of the generator, and the failure determination section is configured to detect the If the difference between the oil temperature of the generator and the oil temperature of the generator when the driving condition is satisfied exceeds a fourth predetermined threshold value, a failure determination of the transaxle oil temperature sensor may be performed.
As a result, the oil temperature of the generator is used as a prerequisite for failure determination of the transaxle oil temperature sensor, and the transaxle oil temperature is By performing failure determination of the axle oil temperature sensor, the reliability of failure determination can be improved.

Preferably, the vehicle includes an outside temperature detection section that detects an outside temperature of the vehicle, and the failure determination section changes at least one of the first threshold value and the second threshold value based on the outside temperature.
Thereby, it is possible to appropriately set at least one of the first threshold value and the second threshold value, thereby improving the reliability of failure determination of the transaxle oil temperature sensor.

Preferably, the vehicle includes an outside temperature detection section that detects outside temperature of the vehicle, and the failure determination section changes the predetermined time based on the outside temperature.
Thereby, it is possible to appropriately set the driving conditions and improve the reliability of failure determination of the transaxle oil temperature sensor.

According to the transaxle oil temperature sensor failure determination device of the present invention, the failure of the transaxle oil temperature sensor is determined when both the first determination and the second determination are satisfied, so that the transaxle oil temperature is normal. It is possible to suppress erroneous determination that the sensor is malfunctioning and improve the accuracy of malfunction determination.

1 is an overall configuration diagram of a travel drive system of a vehicle in which a transaxle oil temperature sensor failure determination device of the present embodiment is adopted. 3 is a flowchart showing a procedure of failure determination control executed in the oil temperature sensor failure determination device. 5 is a time chart showing an example of changes in various data when determining whether an oil temperature sensor is stuck.

Hereinafter, an embodiment in which the present invention is applied to a hybrid vehicle (hereinafter referred to as vehicle 1) will be described.
FIG. 1 is an overall configuration diagram of a travel drive system of a vehicle 1 in which an oil temperature sensor failure determination device of this embodiment is adopted.

The vehicle 1 of this embodiment is a hybrid vehicle that includes a front motor 2 (driving device), a rear motor 5, and an engine 3 (driving device) as traveling drive sources.
The vehicle 1 is a four-wheel drive vehicle configured such that the front wheels 4 are driven by the output of the front motor 2 or the outputs of the front motor 2 and the engine 3, and the rear wheels 6 are driven by the output of the rear motor 5.

The output shaft of the engine 3 is connected to a drive shaft 8, which is a drive shaft for the front wheels 4, via a transaxle 7. The transaxle 7 has a built-in clutch 9 that can connect and disconnect a differential 7b and a power transmission path in a case 7a, and also contains lubricating oil. When the clutch 9 is engaged, the driving force of the engine 3 is transmitted to the front wheels 4 via the transaxle 7 and the drive shaft 8, and when the clutch 9 is disengaged, the engine 3 and the front wheels 4 are disconnected.

The drive shaft of the front motor 2 is connected to a drive shaft 8 via a transaxle 7, and the driving force of the front motor 2 is transmitted from the transaxle 7 via the drive shaft 8 to the front wheels 4. Further, a motor generator 10 (generator) is connected to the upstream side (engine 3 side) of the clutch 9 of the transaxle 7 in the power transmission direction, and generates electricity by driving the engine 3. Furthermore, the motor generator 10 also functions as a starter motor that starts the engine 3 when the clutch 9 is disengaged. The rear motor 5 is connected to a drive shaft 12 of the rear wheel 6 via a reduction gear 11, and its driving force is transmitted from the reduction gear 11 to the rear wheel 6 via the drive shaft 12.

Further, the case 7a of the transaxle 7 and the case of the motor generator 10 of this embodiment are connected to be integrated, and the transaxle 7 and the motor generator 10 have a structure that facilitates mutual heat conduction. There is.

An engine control unit 14 composed of an input/output device, a storage device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc. is connected to the engine 3. The throttle opening, fuel injection amount, ignition timing, etc. are controlled.

The front motor 2, the rear motor 5, and the motor generator 10 are, for example, three-phase AC motors, and are provided with a storage battery 15 for running drive as their power source. The storage battery 15 is composed of a secondary battery such as a lithium ion battery, and includes a battery monitoring unit 15a that calculates its charging rate and detects its temperature.

The front motor 2 and motor generator 10 are connected to a storage battery 15 via a front motor control unit 16. The front motor control unit 16 includes a front motor inverter 16a and a motor generator inverter 16b. The DC power of the storage battery 15 is converted into three-phase AC power by a front motor inverter 16a and a motor generator inverter 16b, and is supplied to the front motor 2 and the motor generator 10. Furthermore, the regenerated power by the front motor 2 and the power generated by the motor generator 10 are converted into DC power by the front motor inverter 16 a and the motor generator inverter 16 b, and the storage battery 15 is charged with the DC power.

The rear motor 5 is connected to a storage battery 15 via a rear motor control unit 17. The rear motor control unit 17 is equipped with a rear motor inverter 17a. The DC power of the storage battery 15 is converted to three-phase AC power by the rear motor inverter 17a and supplied to the rear motor 5, and the regenerated power by the rear motor 5 is converted to DC power by the rear motor inverter 17a and charged to the storage battery 15. .
The vehicle 1 is also equipped with a charger 13 that charges the storage battery 15 using an external power source.

The vehicle 1 is equipped with a hybrid control unit 18 that is a control device for comprehensively controlling the vehicle 1. The hybrid control unit 18 includes an input/output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), and the like. The hybrid control unit 18 controls the operating states of the engine 3, front motor 2, motor generator 10, and rear motor 5, as well as the engagement/disengagement state of the clutch 9 of the transaxle 7. On the input side of the hybrid control unit 18, there are a battery monitoring unit 15a, a front motor control unit 16, a rear motor control unit 17, an engine control unit 14, a vehicle speed sensor 20 that detects the traveling speed (vehicle speed V) of the vehicle 1, and the components shown in the figure. An accelerator opening sensor is connected to detect the accelerator opening when the accelerator opening does not occur, and detection and operation information from these devices is input.

Furthermore, a front motor control unit 16, a rear motor control unit 17, a clutch 9 of the transaxle 7, and an engine control unit 14 are connected to the output side of the hybrid control unit 18.
Then, the hybrid control unit 18 switches the driving mode of the vehicle 1 between the EV mode, series mode, and parallel mode based on various detected amounts from the accelerator opening sensor, vehicle speed sensor 20, and the like. For example, in a region where the efficiency of the engine 3 is high, such as a high speed region, the running mode is set to the parallel mode. Further, in the medium and low speed range, switching is performed between the EV mode and the series mode based on the charging rate SOC of the storage battery 15, the required torque for driving the vehicle, etc.

In the EV mode, the clutch 9 of the transaxle 7 is disengaged, the engine 3 is stopped, and the front motor 2 and rear motor 5 are driven by electric power from the storage battery 15 to cause the vehicle 1 to travel.

In the series mode, the clutch 9 of the transaxle 7 is disengaged, the engine 3 is operated to drive the motor generator 10, and the generated power and the power from the storage battery 15 drive the front motor 2 and rear motor 5 to drive the vehicle. Run 1. Note that surplus power of the power generated by the motor generator 10 is charged into a storage battery 15.

In the parallel mode, the clutch 9 of the transaxle 7 is connected and the engine 3 is operated to transmit driving force from the transaxle 7 to the front wheels 4. If there is surplus engine driving force, the front motor 2 regenerates the driving force. However, when the engine driving force is insufficient, electric power from the storage battery 15 is used to assist the front motor 2.

Further, the hybrid control unit 18 calculates the total required output necessary for running the vehicle 1 based on the various detected amounts and operation information, and applies the total required output to the front motor 2 side and rear motor 5 in the EV mode and series mode. In the parallel mode, the power is distributed to the front motor 2 side, the engine 3 side, and the rear motor 5 side. Then, the required output distributed to each, the gear ratio of the transaxle 7 from the front motor 2 to the front wheels 4, the gear ratio of the transaxle 7 from the engine 3 to the front wheels 4, and the reduction gear 11 from the rear motor 5 to the rear wheels 6. Based on the gear ratio of Output a signal.

Based on the command signal from the hybrid control unit 18, the front motor control unit 16 and rear motor control unit 17 calculate target current values that should be passed through the coils of each phase of the front motor 2 and rear motor 5 in order to achieve the required torque. . Then, switching control is performed on the front motor inverter 16a and the rear motor inverter 17a based on the target current value to control the current value of each coil to the target current value and achieve each required torque. The same applies when the motor generator 10 generates power, and the motor generator inverter 16b is switched and controlled based on the target current value determined from the negative required torque, thereby achieving the target current value.

The engine control unit 14 calculates target values for throttle opening, fuel injection amount, ignition timing, etc. to achieve the required torque based on the command signal from the hybrid control unit 18, and performs control based on these target values to request the torque. Achieve torque.
The vehicle 1 of this embodiment is equipped with a T/A oil temperature sensor 30 (transaxle oil temperature sensor) that detects the lubricating oil temperature (oil temperature) of the transaxle 7. Further, a generator oil temperature sensor (hereinafter referred to as GEN oil temperature sensor 32 (generator oil temperature detection section)) that detects the temperature of oil for cooling the motor generator 10 is provided.

The hybrid control unit 18 includes a failure determination section 31 that determines whether the T/A oil temperature sensor 30 has failed.
The oil temperature sensor failure determination control in the failure determination section 31 will be described below with reference to FIGS. 2 and 3. In this embodiment, the T/A oil temperature sensor 30 is fixed when the detected value of the T/A oil temperature sensor 30 remains at a constant value even though the oil temperature of the transaxle 7 has actually changed. It is determined that this is a failure.

The failure determination unit 31 inputs the oil temperature Tt/a of the transaxle 7 from the T/A oil temperature sensor 30 and the oil temperature Tge of the motor generator 10 from the GEN oil temperature sensor 32 when the vehicle is powered on. At the same time, the cumulative value of the amount of change in the oil temperature Tt/a of the transaxle 7 for each unit time set as appropriate is stored.

FIG. 2 is a flowchart showing a procedure of oil temperature sensor failure determination control executed by the failure determination unit 31.
The oil temperature sensor failure determination control of this embodiment is executed when the power supply of the vehicle is ON.

First, it is determined whether the ignition switch (IG switch), which is the power switch of the vehicle, is ON. If the IG switch is ON, the process advances to step S20. If the IG switch is OFF, the process advances to step S120.
In step S20, it is determined whether the power supply voltage of the hybrid control unit 18 is 10V or more. This threshold value of 10V is a value near the lower limit of the power supply voltage within a range in which the hybrid control unit 18 operates normally. If the power supply voltage is 10V or higher, the process advances to step S30. If the power supply voltage is less than 10V, the process advances to step S120.

In step S30, it is determined whether the detection information of the T/A oil temperature sensor 30 can be used. Regarding whether or not the detection information of the T/A oil temperature sensor 30 can be used, for example, when the hybrid control unit 18 starts up (when the power is turned on), the detected value of the T/A oil temperature sensor 30 is If it is determined that there is no failure in the D-converting circuit, it is determined that the detection information of the T/A oil temperature sensor 30 can be used, or based on the output value of the T/A oil temperature sensor 30. and make judgments. When making a determination based on the output value of the T/A oil temperature sensor 30, for example, if the oil temperature Tt/a, which is the output value of the T/A oil temperature sensor 30, is greater than the output value T1 at the time of a ground fault and the wire is disconnected. Or, it can be used when the output value at the time of a power supply fault is less than T2 (see the graph of Tt/a in Figure 3), and the output value at the time of a ground fault is less than or equal to T1, or the output value at the time of a disconnection or power supply fault is greater than or equal to T2. In this case, it is considered unusable. If the detection information of the T/A oil temperature sensor 30 is usable, the process advances to step S40. If the detection information of the T/A oil temperature sensor 30 is unusable, the process advances to step S120.

In step S40, it is determined whether the circuit of the T/A oil temperature sensor 30 is in failure. In this step, for example, if the determination based on the output value of the T/A oil temperature sensor 30 performed in step S30 continues for a certain period of time (several 100 msec), it is determined that the circuit of the T/A oil temperature sensor 30 is not in failure. All you have to do is judge. If the circuit of the T/A oil temperature sensor 30 is not out of order, the process advances to step S50. If the circuit of the T/A oil temperature sensor 30 is out of order, the process advances to step S120.

In step S50, the oil temperature Tge of the motor generator 10 at the time of starting the vehicle is input from the GEN oil temperature sensor 32, and it is determined whether the oil temperature Tgea at the time of starting is equal to or lower than a third threshold value (45° C.). This third threshold value of 45° C. is a value close to the highest value of oil temperature Tge of motor generator 10 after soaking. If the oil temperature Tgea at startup is 45° C. or lower, the process advances to step S60. If the oil temperature Tgea at the time of startup exceeds 45° C., the process advances to step S120.

In step S60, it is determined whether the running conditions are satisfied. The driving condition is that the cumulative time Σtv during which the vehicle speed V has been 40 km/h or more since the start has exceeded a predetermined time (300 seconds). If the running conditions are satisfied, the process advances to step S70. If the running conditions are not met, step S60 is repeated.

In step S70, the oil temperature Tge of the motor generator 10 is input from the GEN oil temperature sensor 32, and the oil temperature Tgeb of the motor generator 10 when this running condition is satisfied and the oil temperature Tgeb of the motor generator 10 at the time of startup stored in the storage device are input. It is determined whether the absolute value of the difference between the oil temperature Tgea and the oil temperature Tgea (|Tgeb−Tgea|) is larger than a fourth threshold value (10° C.). The fourth threshold value of 10° C. may be set to a temperature difference of the motor generator 10 such that the oil temperature of the transaxle 7 reliably changes more than the first threshold value of 2° C. in step S80 below. If the absolute value of the difference in oil temperature of motor generator 10 (|Tgeb−Tgea|) is greater than 10° C., the process advances to step S80. If the absolute value of the oil temperature difference (|Tgeb−Tgea|) of motor generator 10 is 10° C. or less, the process advances to step S120.

In step S80, the oil temperature Tt/a of the transaxle 7 is input from the T/A oil temperature sensor 30, and the oil temperature Tt/ab of the transaxle 7 when this running condition is satisfied is stored in the storage device. It is determined whether the absolute value of the difference from the oil temperature Tt/aa of the transaxle 7 at the time of startup is less than a first threshold value (2° C.). This first threshold value of 2° C. may be set to a value such that the oil temperature of the transaxle 7 changes reliably when the driving conditions are met. If the absolute value of the difference in oil temperature of the transaxle 7 (|Tt/ab−Tt/aa|) is less than 2° C., the process advances to step S90. If the absolute value of the difference in oil temperature of the transaxle 7 (|Tt/ab−Tt/aa|) is 2° C. or higher, the process advances to step S110. Note that the determination in this step corresponds to the first determination of the present invention.

In step S90, the value (Σ|change amount of Tt/a|) obtained by integrating the absolute value of the amount of change in the oil temperature Tt/a of the transaxle 7 within a unit time from the time of startup is determined to be a second threshold value (2° C. ). If the integrated value of the absolute value of the amount of change in oil temperature Tt/a (Σ|amount of change in Tt/a|) is less than 2° C., the process advances to step S100. If the integrated value of the absolute value of the amount of change in oil temperature Tt/a (Σ|change amount in Tt/a|) is 2° C. or more, the process advances to step S110. Note that the determination in this step corresponds to the second determination of the present invention.

In step S100, it is determined that the T/A oil temperature sensor 30 is stuck. Then, this routine ends.
In step S110, it is determined that the T/A oil temperature sensor 30 is normal. Then, this routine ends.
In step S120, in the oil temperature sensor failure determination control during the current startup, it is determined that the determination is incomplete because it has not been possible to determine whether or not the T/A oil temperature sensor 30 is normal. Then, this routine ends.

Then, the hybrid control unit 18 controls the warning display and the output of the engine 3 and each

motor

2 and 5 based on the determination result of the failure determination control in the failure determination section 31. For example, if the T/A oil temperature sensor 30 is determined to be malfunctioning, there is a possibility that the oil temperature will be erroneously determined to be high and control will be performed to suppress the output of the front side (engine 3 and front motor 2). The oil temperature of the transaxle 7 is set at 80°C.

In the vehicle equipped with the failure determination unit 31 of this embodiment, for example, as shown in FIG. The running condition is satisfied when the cumulative time Σtv becomes equal to or longer than a predetermined time (300 seconds). Under the condition that the absolute value of the difference in the oil temperature of the motor generator 10 (|Tgeb - Tgea|) is greater than 10°C when the running conditions are satisfied, the absolute value of the difference in the oil temperature of the transaxle 7 (|Tt/ab - Tt T/A oil A failure determination (sticking abnormality determination) of the temperature sensor 30 is made. Note that FIG. 3 shows a case where the vehicle stops running after determining that the T/A oil temperature sensor 30 has failed.

As described above, the hybrid control unit 18 of the vehicle 1 according to the present embodiment includes the failure determination section 31 that determines a failure of the T/A oil temperature sensor 30 that detects the oil temperature of the transaxle 7.

The failure determination unit 31 determines the absolute value of the difference (|Tt/ab -Tt/aa|) is less than the first threshold value (2°C), and the amount of change in the oil temperature of the transaxle 7 per unit time from the time of startup to the time when the running conditions are satisfied. If the second judgment is made to determine that the integrated value of the absolute value (Σ|change amount of Tt/a|) is less than the second threshold (2°C), and both the first judgment and the second judgment are satisfied. It is determined that the T/A oil temperature sensor 30 is stuck.

The driving conditions are that the cumulative time Σtv during which the vehicle speed V has been 40 km/h or more since the start has exceeded a predetermined time (300 seconds), and the oil temperature of the transaxle 7 has risen by a first threshold value or more. Therefore, it can be determined by the first determination that the T/A oil temperature sensor 30 is in a fixed state.

The failure determination unit 31 determines that the T/A oil temperature sensor 30 is stuck when not only the first determination but also the second determination is satisfied. As a result, even if the oil temperature of the transaxle 7 at the time of starting and when the running conditions are satisfied is coincidentally almost the same, the second determination can be made if the oil temperature of the transaxle 7 increases or decreases from the time of starting until the running conditions are met. Failure is not determined because it does not hold true. Therefore, erroneous failure determination can be avoided, and the accuracy of failure determination of the T/A oil temperature sensor 30 can be improved.

In addition, the running condition is not the elapsed time since the start, but the cumulative time Σtv during which the vehicle speed V has been 40 km/h or more since the start has exceeded a predetermined time (300 seconds). Even if the vehicle speed temporarily becomes less than 40 km/h before the driving condition is established, the driving condition can be quickly established by increasing the vehicle speed V to 40 km/h or more after that, and the T/A oil temperature sensor 30 The determination time required for failure determination can be shortened. Further, the failure determination unit 31 inputs the oil temperature Tge of the motor generator 10 from the GEN oil temperature sensor 32, and when the oil temperature Tgea of the motor generator 10 is equal to or lower than a third threshold value (45° C.) at the time of starting, /A Execute failure determination of the oil temperature sensor 30.

As a result, by using the GEN oil temperature sensor 32 that is integrated with the transaxle 7 (arranged adjacent to it) and detects the oil temperature of the motor generator 10 that has substantially the same temperature, the transaxle 7 at the time of starting By performing failure determination of the T/A oil temperature sensor 30 in an environment where the oil temperature of the T/A oil temperature sensor 30 is low and the oil temperature of the transaxle 7 changes significantly between the time of starting and the establishment of driving conditions. , the reliability of failure determination of the T/A oil temperature sensor 30 can be improved.

Further, if the oil temperature Tgea of the motor generator 10 exceeds the third threshold value at the time of starting, the failure determination of the T/A oil temperature sensor 30 is not executed, so that the T/A oil temperature sensor 30 is determined to be normal. Nevertheless, it is possible to avoid erroneously determining that the transaxle 7 is malfunctioning due to the inability to obtain a large change in the oil temperature, thereby improving the reliability of the failure determination of the T/A oil temperature sensor 30.

Further, if the difference between the oil temperature Tgea of the motor generator 10 at the time of starting and the oil temperature Tgea of the motor generator 10 when the driving condition is satisfied exceeds a fourth threshold value (10°C), the T/A oil temperature sensor 30 failure determinations are performed.

As a result, the oil temperature Tgea of the motor generator 10 at the time of starting and the oil temperature Tgeb of the motor generator 10 when the driving condition is satisfied are used as prerequisites for failure determination of the T/A oil temperature sensor 30, and a predetermined value is set from the time of starting. By executing the failure determination of the T/A oil temperature sensor 30 when a large change in oil temperature of the motor generator 10 is obtained before the driving condition is satisfied, the reliability of the failure determination can be improved.

Also, failure determination of the T/A oil temperature sensor 30 is not performed when there is little change in the oil temperature of the motor generator 10 from start to when the running conditions are met, that is, when there is little change in the oil temperature of the transaxle 7. This makes it possible to improve the reliability of failure determination of the T/A oil temperature sensor 30.

This concludes the description of the embodiment, but aspects of the present invention are not limited to this embodiment.
For example, if the vehicle 1 is equipped with an outside air temperature sensor 40 (an outside air temperature detection unit) that detects outside air temperature, and the failure determination unit 31 changes at least one of the first threshold value and the second threshold value based on the outside air temperature, good. For example, as the outside air temperature at startup increases, the oil temperature in the transaxle 7 at startup increases, making it difficult for the temperature of the transaxle 7 to rise during driving, so it is recommended to set the first threshold value and the second threshold value small. . Thereby, the failure determination accuracy of the T/A oil temperature sensor 30 can be improved.

Additionally, the driving conditions may be changed based on the outside temperature. For example, the predetermined time period may be set to be longer as the outside air temperature at the time of startup becomes higher. As a result, in accordance with the situation where the temperature of the transaxle 7 is difficult to rise due to driving, when the T/A oil temperature sensor 30 is stuck abnormally, the first judgment and the second judgment when the driving condition is satisfied are reliably established, and the T/A The failure determination accuracy of the oil temperature sensor 30 can be improved.

Further, the details of various threshold values for determination in the oil temperature sensor failure determination control may be changed as appropriate. In the oil temperature sensor failure determination control described above, the present invention may perform at least determinations in steps S60, S80, and S90.

Further, in the above embodiment, the present invention is applied to a hybrid vehicle that can switch between EV mode, series mode, and parallel mode, but the present invention can be widely applied to vehicles having a transaxle oil temperature sensor.
Furthermore, it is applicable to plug-in hybrid vehicles (PHEVs) that can be externally charged or externally powered.

1 Vehicle 2 Front motor (drive equipment)
3 Engine (drive equipment)
7 Transaxle 8 Drive shaft 10 Motor generator (generator)
18 Hybrid control unit 30 T/A oil temperature sensor (transaxle oil temperature sensor)
31 Failure determination section 32 GEN oil temperature sensor (generator temperature detection section)
40 Outside air temperature sensor (outside air temperature detection section)

Claims

A failure determination device for a transaxle oil temperature sensor that is installed in a vehicle equipped with a transaxle that transmits power between a drive device that outputs power and a drive shaft, and that detects the oil temperature of the transaxle,
comprising a failure determination unit that determines a failure of the transaxle oil temperature sensor based on the oil temperature of the transaxle from the time of starting the vehicle until the establishment of a predetermined running condition;
The failure determination unit includes:
a first determination that determines that a difference between an oil temperature of the transaxle when the vehicle is started and an oil temperature of the transaxle when the driving condition is satisfied is less than a predetermined first threshold;
performing a second determination to determine that an integrated value of the absolute value of the amount of change in the oil temperature of the transaxle per unit time from the time of the start to the time the driving condition is satisfied is less than a predetermined second threshold;
A failure determination device for a transaxle oil temperature sensor, characterized in that the transaxle oil temperature sensor is determined to be in failure when both the first determination and the second determination are satisfied.
2. The failure determination device for a transaxle oil temperature sensor according to claim 1, wherein the running condition is that the cumulative time during which the running speed of the vehicle has been at least a predetermined speed since the start of the vehicle is at least a predetermined time.
The vehicle includes a generator disposed adjacent to the transaxle, and a generator oil temperature detection unit that detects oil temperature of the generator,
The failure determination unit executes failure determination of the transaxle oil temperature sensor when the oil temperature of the generator is equal to or lower than a predetermined third threshold value at the time of the start-up. Failure determination device for transaxle oil temperature sensor.
The vehicle includes a generator disposed adjacent to the transaxle, and a generator oil temperature detection unit that detects oil temperature of the generator,
When the absolute value of the difference between the oil temperature of the generator at the time of the startup and the oil temperature of the generator when the driving condition is satisfied exceeds a fourth predetermined threshold value, the failure determination unit: The transaxle oil temperature sensor failure determination device according to claim 1, wherein the transaxle oil temperature sensor failure determination device executes failure determination of the transaxle oil temperature sensor.
comprising an outside air temperature detection section that detects outside air temperature of the vehicle,
The failure determination device for a transaxle oil temperature sensor according to claim 1, wherein the failure determination unit changes at least one of the first threshold value and the second threshold value based on outside temperature.
comprising an outside air temperature detection unit that detects outside air temperature of the vehicle,
3. The transaxle oil temperature sensor failure determination device according to claim 2, wherein the failure determination section changes the predetermined time based on outside air temperature.