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Electronically-controlled, adaptive automatic transmission system

  • US 4,875,391 A
  • Filed: 04/29/1988
  • Issued: 10/24/1989
  • Est. Priority Date: 04/29/1988
  • Status: Expired due to Fees
First Claim
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1. In an automatic transmission having a plurality of gears for transmitting power from a prime mover to a load device over desired ranges of torque and speed, and an assembly of friction elements, with hydraulic fluid associated with the operation of the friction elements, the friction elements for selectively disengaging and engaging the gears from the prime mover, a control system for controlling the selection and engagement of the gears, comprising:

  • means for sensing the input and output speeds of the transmission;

    means for sensing the power demand on the prime mover;

    means for providing an indication of an operator selected mode of operation for the transmission;

    means for controlling the flow of hydraulic fluid associated with the operation of the friction elements; and

    electronic controller means for controlling the actuation of the means for controlling the flow of hydraulic fluid to regulate the application and release of pressure to and from the friction elements in response to signals from the means for sensing the input and output speeds of the transmission, the means for sensing the power demand on the prime move, and the means for providing an indication of an operated selected mode of operation for the transmission, the controller means for controlling the actuation of the means for controlling the flow of hydraulic fluid by making adjustments to a duty cycle of the means for controlling the flow of hydraulic fluid such that the adjustments are made continuously in a real time, closed loop manner for causing the transmission to follow a set of predetermined shift schedules.

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