US Patent 7481738 Controlling a gear ratio in a continuously variable transmission

This invention provides a method for controlling a gear ratio in an automatic transmission of a vehicle. The method includes detecting a desired engine braking condition associated with the vehicle. Once the engine braking condition is determined, a decay factor is determined for reducing the gear ratio of the transmission. The decay factor maintains the gear ratio for a delayed period of time before gradually reducing the gear ratio over time. After determining the decay factor, the gear ratio of the transmission is controlled in accordance with the decay factor.