Patent ID: 6506141
Filing Date: 2003-01-14
Classification: F16H,Y10T

Abstract:
A method and strategy for controlling ratios of a multiple-ratio transmission for an automotive vehicle having a throttle-controlled engine and traction wheels, the transmission having pressure-operated clutches and brakes for establishing and disestablishing the ratios, the vehicle including traction control wherein torque at the traction wheels is modified when incipient traction wheel slip is detected as engine torque is reduced;determining a first shift point schedule from a set of shift point schedules as a function of driver commanded torque for each transmission ratio whereby optimum performance and fuel economy is obtained when the vehicle operates without traction control activated; determining a second shift point schedule from a set of shift point schedules as a function of torque commanded by the traction control for each transmission ratio when the vehicle operates in a traction control mode; determining a synthetic throttle setting as a function of engine speed and torque; controlling the operating pressure of the clutches and brakes as a function of synthetic throttle setting; determining vehicle speed shift points during operation of the vehicle without traction control as determined by the first set of shift point schedules; and determining vehicle speed shift points during operation of the vehicle in a traction control mode as determined by the second set of shift point schedules whereby the highest gear ratio possible is obtained during operation of the vehicle in the traction control mode and the gear ratio for optimum performance and fuel economy is obtained during operation of the vehicle in each gear ratio without traction control.