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Lock-up control apparatus for automatic transmission

  • US 5,667,458 A
  • Filed: 07/07/1995
  • Issued: 09/16/1997
  • Est. Priority Date: 07/08/1994
  • Status: Expired due to Term
First Claim
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1. A lock-up control apparatus for an automatic transmission, including a torque converter which can be turned into a lock-up state by a lock-up clutch so that input and output elements of the torque converter are directly connected with each other, comprising:

  • a coasting drive detecting means for detecting a coasting drive including a deceleration operation of a vehicle;

    a sudden deceleration detecting means for detecting a large deceleration rate above a predetermined value of the vehicle; and

    a coasting drive lock-up capacity controlling means for controlling an application capacity of the lock-up clutch to a minimum application capacity within such a range that a relative rotation is not generated between the input and output elements of the torque converter in a period when the deceleration rate of the vehicle is below the predetermined value during the coasting drive, in response to signals from both the detecting means,wherein the coasting drive lock-up capacity controlling means comprises;

    a reverse driving torque detecting means for detecting a reverse driving torque of an engine in a forward speed of the automatic transmission; and

    a coasting drive lock-capacity operating means for calculating a minimum application capacity of the lock-up clutch within such a range that the relative rotation is not generated between the input and output elements of the torque converter from the reverse driving torque detected by the reverse driving torque detecting means, thereby controlling the application capacity of the lock-up clutch by a command value corresponding with the application capacity calculated by the coasting drive lock-up capacity operating means.

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