Patent ID: 6258009
Filing Date: 2001-07-10
Classification: B60K,B60W,F16H,Y10T

Abstract:
A method of operating a drive train assembly for a vehicle including a source of rotational power, a transmission connected to the source of rotational power and operable in a plurality of transmission gear ratios, an axle assembly connected to the transmission and operable in a plurality of axle gear ratios, and a controller for operating the transmission in a desired one of the plurality of transmission gear ratios and for operating the axle assembly in a desired one of the plurality of axle gear ratios to provide a desired overall gear ratio for the vehicle, said method comprising the steps of:(a) reducing the amount of torque that is being generated by the source of rotational power to a relatively low level;(b) pre-selecting a shift to an appropriate speed reduction gear ratio in the axle assembly;(c) causing a shifting process to occur within the axle assembly;(d) causing the rotational speed of the source of rotational power to be synchronized with a calculated anticipated rotational speed of the output shaft of the transmission after the shifting process within the axle assembly has been completed; and(e) increasing the amount of torque that is being generated by the source of rotational power.