Patent ID: 7920949
Filing Date: 2011-04-05
Classification: F16H,Y10T

Abstract:
1. A method of controlling an output torque of a variator having a hydraulic actuator responsive to an actuator pressure signal, the method comprising: receiving an indication of a first expected output torque; evaluating a plurality of parameters related to operation of the variator; reading a map to link the plurality of parameters to a first mapped value for the actuator pressure signal, wherein the first expected output torque is associated with the first mapped value; applying the first mapped value to the hydraulic actuator as the actuator pressure signal; measuring a first output torque of the variator and comparing the first output torque to the first expected output torque to derive an error value; determining whether the error value conforms to at least one modification condition; replacing the first mapped value of the map with a modified value if it is determined that the error value conforms to at least one modification condition; determining whether the error value exceeds a first error limit value, and producing a system error signal if it is determined that the error value exceeds the first error limit value; and determining whether the error value has exceeded a second error limit value that is less than the first error limit value, and if so, whether the error value has exceeded the second error limit value more than a predetermined number of times, and producing the system error signal if the error value has exceeded the second error limit value more than the predetermined number of times.