Gm Global Technolgoy Operations, Inc.

Elton L Thompson

James F Hartz

Reece R Fuehrer

A multispeed transmission having an automatic shift control system having an automatic shift valve which is biased for upshift by a force increasing with output speed of the transmission and is biased for downshift by a force increasing concurrently with torque demand, to provide upshifts at speeds increasing with torque demand and downshifts at lower speeds. The shift valve controls the supply of shift fluid pressure to the ratio-engaging devices to establish low and high ratio drives. A regulator valve increases the shift fluid pressure with an increasing lagging torque demand signal. A modulator valve is controlled by an engine fuel feed or throttle to provide a concurrent torque demand signal pressure concurrent with throttle movement for the shift valve. The lagging torque demand signal is more concurrent with engine torque and power, such as the gasifier pressure of a gas turbine engine, or the supercharger pressure of an internal combustion engine. The transmission is shifted immediately in response to torque demand, and the shift pressure is proportional to the engine torque and speed at the time of the shift.

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Indianapolis, IN, United States of America

Elton L Thompson