Patent ID: 6231474
Filing Date: 2001-05-15
Classification: B60W,F16H,Y10T

Abstract:
A method for controlling automatic downshifting in a vehicular automated mechanical transmission system (10) for a vehicle equipped with a manually operated foot brake system and a manually operated engine brake system, said automated mechanical transmission system comprising a fuel controlled engine (12), a multiple-speed mechanical transmission (14), and a controller (28) for receiving input signals (30) including one or more of signals indicative of engine speed (ES), foot brake system operation (FB), and engine brake system operation (EB), and to process said input signals in accordance with with logic rules to issue command output signals (32) to transmission system actuators including a transmission actuator (52) effective to shift said transmission, said method characterized by:(i) establishing a default value (62) for engine speed at which a downshift will be commanded;(ii) sensing for operation of said engine brake system (EB);(iii) if engine brake system operation is sensed, then increasing the value of engine speed at which downshifts will be commanded (ES.sub.D/S) to a first increased value (66) greater than said default value.