Patent ID: 8606474

Claim:
A method for controlling a continuously variable transmission (CVT), the method comprising: receiving vehicle operation data; and controlling engine and transmission operations based on the vehicle operation data, fuel efficiency data, and CVT efficiency data, wherein said receiving vehicle operation data and said controlling engine and transmission operations are performed by at least one processor, and said controlling engine and transmission operations include the processes of: determining an optimal engine speed based on the vehicle operation data and the fuel efficiency data; determining a fixed-speed mode speed based on the fuel efficiency data; if the optimal engine speed is equal to or greater than the fixed-speed mode speed: determining an overall CVT ratio that is based on the fixed-speed mode speed, a vehicle speed, and the CVT efficiency data; and controlling the transmission operations in a fixed-speed mode such that engine speed is maintained at the fixed-speed mode speed, engine torque is a function of vehicle operation conditions, and the determined overall CVT ratio based on the fixed-speed mode speed; and if the optimal engine speed is less than the fixed-speed mode speed: determining an overall CVT ratio that is based on the optimal engine speed, the vehicle speed, and the CVT efficiency data, and controlling the transmission operations in an optimal-operation mode such that engine torque is a function of a varying engine speed and the determined overall CVT ratio based on the optimal engine speed.