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Electronically controlled automatic transmission and method of controlling the same

  • US 4,896,569 A
  • Filed: 06/16/1988
  • Issued: 01/30/1990
  • Est. Priority Date: 06/26/1987
  • Status: Expired due to Term
First Claim
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1. A method of electronically controlling an automatic transmission in which the transmission gear stage and engaging or disengaging operations of a lock-up clutch in a torque converter are determined on the basis of the number of transmission output revolutions and the throttle opening and in which a shifting solenoid and a lock-up solenoid incorporated in said transmission are controlled, said method comprising the steps of:

  • (a) comparing the number of transmission input revolutions and the number of transmission output revolutions with each other;

    (b) determining whether or not the number of transmission output revolutions is abnormal on the basis of the result of said comparison; and

    (c) detecting existence of an internal mechanical failure of said transmission by comparing the number of revolutions output from a transmission output sensor with the number of transmission output revolutions calculated from the number of transmission input revolutions and the gear ratio, if no abnormality is determined to exist.

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