Controller and control method for vehicle

1. A controller for a vehicle, the vehicle including an internal combustion engine, a motor that starts the internal combustion engine, and a battery that supplies power to the motor, wherein the controller is configured to execute:

a lubricating oil degradation degree acquisition process that calculates a degradation degree of a lubricating oil that lubricates the internal combustion engine;

a battery degradation degree acquisition process that calculates a degradation degree of the battery;

an oil change time calculation process that calculates an oil change time for the lubricating oil from the degradation degree of the lubricating oil and the degradation degree of the battery, and the oil change time calculation process includes calculating the oil change time so as to become earlier as the degradation degree of the battery increases; and

an output process that outputs to a display a notification based on the oil chance time.

2. The controller according to claim 1 , wherein

the controller is configured to execute an ambient temperature acquisition process that obtains a predicted temperature outside the vehicle when the internal combustion engine is started next, and

the controller executes the oil change time calculation process when the predicted temperature is lower than a preset specific temperature.

3. The controller according to claim 2 , wherein

the vehicle includes an ambient temperature sensor that measures a temperature outside the vehicle, and

the ambient temperature acquisition process includes obtaining the predicted temperature by estimating the predicted temperature from changes in an ambient temperature over a fixed period obtained from the ambient temperature sensor.

4. The controller according to claim 2 , wherein

the vehicle includes a communication device capable of communicating with a device outside the vehicle,

the controller is configured to execute a data acquisition process that obtains, through the communication device, ambient temperature data related to a future temperature outside the vehicle, and

the ambient temperature acquisition process includes obtaining the predicted temperature by estimating the predicted temperature from the ambient temperature data obtained by the data acquisition process.

5. The controller according to claim 2 , further comprising a memory device that stores multiple periods into which a specific fixed period is divided and stores a temperature corresponding to each of the multiple periods, wherein

the controller is configured to execute a date-and-time acquisition process that obtains a date and time when the internal combustion engine is started, and

the ambient temperature acquisition process includes obtaining the predicted temperature by estimating, as the predicted temperature, a temperature corresponding to one of the periods that includes the date and time.

6. The controller according to claim 2 , wherein

the controller is configured to execute a next start estimation process that estimates a next start time at which the internal combustion engine is started next, and

the ambient temperature acquisition process includes obtaining, as the predicted temperature, a temperature outside the vehicle at the next start time obtained by the next start estimation process.

7. The controller according to claim 1 , wherein

the controller is configured to execute an ambient temperature acquisition process that obtains a predicted temperature outside the vehicle when the internal combustion engine is started next, and

the oil change time calculation process includes calculating the oil change time so as to become earlier as the predicted temperature decreases as compared with when the predicted temperature increases.

8. A method for controlling a vehicle, the vehicle including an internal combustion engine, a motor that starts the internal combustion engine, and a battery that supplies power to the motor, the method comprising:

calculating a degradation degree of a lubricating oil that lubricates the internal combustion engine;

calculating a degradation degree of the battery;

calculating an oil change time for the lubricating oil from the degradation degree of the lubricating oil and the degradation degree of the battery, wherein the calculating the oil change time includes calculating the oil change time so as to become earlier as the degradation degree of the battery increases; and

outputting to a display a notification based on the oil change time.