Patent ID: 6325743
Filing Date: 2001-12-04
Classification: B60W,F16H,Y10T

Abstract:
A method for controlling automatic upshifting in a vehicular automated mechanical transmission system (10) for a vehicle comprising a fuel-controlled engine (12), a multiple-speed mechanical transmission (14) having an input shaft (18) driven by said engine, a brake (ECB, 26) for selectively retarding rotation of said input shaft, and a controller (28) for receiving input signals (30) including one or more of signals indicative of engine speed (ES), engaged gear ratio (GR) and vehicle speed (OS), and to process said input signals in accordance with logic rules to issue command output signals (32) to transmission system actuators including a transmission actuator (52) effective to shift said transmission and a brake actuator effective to operate said brake, said method characterized by:(i) establishing a maximum acceptable time (T.sub.MAX) for completion of upshifts;(ii) establishing an upshift feasibility criteria whereby upshifts into a target gear ratio are considered feasible only if, under sensed vehicle operating conditions,(a) upshifts can be accomplished within a time no greater than said maximum available time (T<T.sub.MAX);(b) substantial synchronization can be obtained above a predetermined engine speed; and(c) at engagement of the target ratio, the vehicle will be capable of at least a predetermined acceleration (dOS/dt);(iii) upon sensing a requirement (ES>ES.sub.U/S) for an upshift from an engaged gear ratio (GR), in sequence:(a) determining if a skip upshift of two ratios from the currently engaged ratio (GR.sub.TARGET =GR+2) is feasible and, if so, commanding a skip upshift of two ratios from the currently engaged ratio; if not,(b) then determining if a single upshift (GR.sub.TARGET =GR+1) without using said brake is feasible and, if feasible, commanding a single upshift from the currently engaged ratio without using said brake; if not,(c) then determining if a single upshift with use of said brake is feasible and, if so, commanding a single upshift from currently engaged ratio using said brake and, if not,(d) then retaining the transmission engaged in the currently engaged ratio.