×

Direct-coupling clutch control method for an automatic transmission

  • US 5,277,287 A
  • Filed: 05/21/1992
  • Issued: 01/11/1994
  • Est. Priority Date: 12/20/1990
  • Status: Expired due to Term
First Claim
Patent Images

1. A direct-coupling mechanism control method for an automatic transmission in a vehicle including a driving force transmission installed between an internal combustion engine and an automatic transmission and which has an input-side driving force transmitting element coupled to a side of the internal combustion engine, an output-side driving force transmitting element coupled to the automatic transmission, and a direct-coupling mechanism for permitting the input and output-side driving force transmitting elements to be coupled to each other, for controlling a coupling state of the direct-coupling mechanism to be in any one of a fully direct-coupled state, in which the input and output-side driving force transmitting elements are integrally coupled to each other;

  • a slip direct-coupled state, in which torque transmission is permitted such that a rotational speed difference between the input-side and output-side driving force transmitting elements falls within a predetermined range; and

    a non-direct-coupled state, in which the fully direct-coupled state and the slip direct-coupled state are released and in which torque transmission, through hydraulic oil, between the input and output-side driving force transmitting elements is permitted, the direct-coupling mechanism control method comprising the steps of;

    (a) determining whether or not the internal combustion engine is running in at least one of a low rotation speed area and a decelerating area and controlling the direct-coupling mechanism to be brought in the slip direct-coupled state when it is determined that the internal combustion engine is running in at least one of the low rotation speed area and the decelerating area;

    (b) determining whether or not a variation in a rotational rate of an input and output shaft of the automatic transmission goes beyond a first permissible range when the direct-coupling mechanism is controlled to be brought in the slip direct-coupled state;

    (c) changing the direct-coupling mechanism from the slip direct-coupled state to the non-direct-coupled state when it is determined that the variation in the rotational rate of the input and output shaft of the automatic transmission goes beyond the first permissible range;

    (d) determining whether or not the variation in the rotational rate of the input and output shaft of the automatic transmission goes beyond a second permissible range after the change to the non-direct-coupled state is made; and

    (e) detecting generation of direct-coupling vibration attributable to the slip direct-coupled state when it is determined that the variation in the rotational rate of the input and output shaft of the automatic transmission goes beyond the second permissible range.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×