Patent ID: 6837323

Claim:
A method for shifting from a first gear ratio to a second gear ratio using an automatic transmission in a vehicle having an engine and an auxiliary boost source for augmenting torque produced by said engine, said method comprising: defining a variable shift schedule comprising at least two gear ratio change parameters each defined by a pair of engine variables relating to vehicle performance; measuring said pair of engine variables to obtain values indicative of vehicle performance for said first gear ratio; comparing said values to said at least two gear ratio change parameters to detect a variable shift condition known to require changing of said first gear ratio; calculating a first boost torque necessary to maintain approximately constant output torque before and after changing said first gear ratio; calculating a second boost torque available from said auxiliary boost source; comparing said first boost torque and said second boost torque to detect a steady output torque condition; shifting from said first gear ratio to said second gear ratio and powering said auxiliary boost source to augment torque available from said engine when said variable shift condition and said steady output torque condition are detected.