Oil temperature estimation apparatus and oil temperature estimation method

An oil temperature estimation method of estimating an oil temperature and performing high temperature protection of a driving system of a vehicle, the oil temperature estimation method comprising:

• detecting an outside air temperature using with an outside air temperature sensor;
• detecting a vehicle speed of the vehicle with a vehicle speed sensor;
• acquiring an estimated oil temperature initial value;
• using, at a start of estimating the oil temperature, the estimated oil temperature initial value as an estimated oil temperature previous value;
• acquiring a saturated oil temperature based on the outside air temperature and the vehicle speed;
• acquiring an oil temperature deviation between the saturated oil temperature and the estimated oil temperature previous value;
• acquiring an oil temperature feedback value based on the oil temperature deviation and the vehicle speed;
• acquiring an estimated oil temperature current value based on the estimated oil temperature previous value and the oil temperature feedback value, the estimated oil temperature current value including a current value of the estimated oil temperature that is estimated one time after the last value of the estimated oil temperature, wherein the estimated oil temperature current value is used as the estimated oil temperature previous value one time after the current value of the estimated temperature in a next estimation of the oil temperature;
• and
• in response to the estimated oil temperature current value being higher than or equal to a predetermined value, restricting the vehicle speed of the vehicle.

An oil temperature estimation apparatus configured to estimate an oil temperature and perform high temperature protection of a driving system of a vehicle, the oil temperature estimation apparatus comprising:

• a vehicle speed sensor configured to detect a vehicle speed of the vehicle;
• an outside air temperature sensor configured to detect an outside air temperature;
• and
• circuitry configured to:
• acquire an estimated oil temperature initial value;
• use, at a start of estimating the oil temperature, the estimated oil temperature initial value as an estimated oil temperature previous value;
• acquire a saturated oil temperature in a running state of the vehicle at least including the vehicle speed based on the running state and on the outside air temperature, the running state at least including the vehicle speed;
• acquire an oil temperature deviation between the saturated oil temperature and the estimated oil temperature previous value;
• acquire an oil temperature feedback value based on the oil temperature deviation and the vehicle speed;
• acquire an estimated oil temperature current value based on the estimated oil temperature previous value and the oil temperature feedback value, the estimated oil temperature current value including a current value of the estimated oil temperature that is estimated one time after the last value of the estimated oil temperature, wherein the estimated oil temperature current value is used as the estimated oil temperature previous value one time after the current value of the estimated temperature in a next estimation of the oil temperature;
• and
• in response to the estimated oil temperature current value being higher than or equal to a predetermined value, restrict the vehicle speed of the vehicle.