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Shift shock suppressing system for automotive power train

  • US 5,577,979 A
  • Filed: 02/13/1995
  • Issued: 11/26/1996
  • Est. Priority Date: 02/15/1994
  • Status: Expired due to Term
First Claim
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1. A shift shock suppressing system for an automotive power train including an engine and an automatic transmission mounted on a vehicle, comprising:

  • shifting control means for performing shift control for said automatic transmission depending upon an operating condition of the engine and a traveling condition of the vehicle;

    torque varying means for varying an output torque of the engine;

    shifting state detecting means for detecting on-going shifting state of the automatic transmission controlled by said shift control means;

    shift shock suppression control means for outputting a command lowering of the output torque of said engine to said torque varying means when initiating of down-shifting is detected by said shifting state detecting means, and when a first predetermined period is elapsed from detection of initiation of down-shifting, and maintaining the command for a second predetermined period;

    arithmetic means for deriving a variation rate of an engine speed after initiation of down-shifting;

    judgement means for judging whether a down-shifting is completed on the basis of an input from said arithmetic means;

    measuring means for measuring a shifting period as a period from initiation of down-shifting to completion of down-shifting as judged by said judgement means; and

    learning control means for modifying said first predetermined period with a value derived by subtracting a preliminarily set third predetermined period from said shifting period derived by said measuring means.

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