Gm Global Technolgoy Operations, Inc.

Scott Mc Thompson

Shushan Bai

Timothy Alan Robinson

Phillip F Mc Cauley

Transmission output speed and engine throttle position are inputs to a control which determines acceleration and input speed. Fuzzy logic has acceleration and throttle membership functions and a set of upshift and downshift values, and rules for weighting each of the values in accordance with the degree of membership of acceleration and throttle position in certain of the functions to determine a downshift point and an upshift point. The input speed is compared to the shift points to decide whether to order a shift. Two or more sets of shift values are stored and are selectable for different performance options. The shift values are stated in terms of a percentage of engine governed speed to allow different engines to be coupled to the transmission. Lockup clutch apply and release logic controls converter lockup to maintain converter mode when significant torque multiplication is occurring and generally to maintain lockup mode when the transmission range is at or above the lowest allowable lockup range.

Fuzzy logic shift scheduling for automatic transmissions

A method and apparatus as presented for monitoring the condition of oil in a transmission to present a service indicia prior to the time that the oil life has been spent. A thermosensor and a tachometer are associated with the transmission to present respective output signals correlated with operating temperature and transmission revolutions. The revolutions of the transmission are weighted as a function of the deviation of the temperature from a temperature standard. The resulting effective revolutions are then applied to a down counter which is initially loaded to the number of allowable effective revolutions when the transmission oil is changed or the transmission serviced. When the down counter has counted out, a message is displayed indicating the need for service.

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Zionsville, IN, United States of America

Scott Mc Thompson