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Control system for automatic vehicle transmissions

  • US 6,516,261 B2
  • Filed: 08/23/1999
  • Issued: 02/04/2003
  • Est. Priority Date: 08/24/1998
  • Status: Expired due to Fees
First Claim
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1. A system for controlling an automatic transmission of a vehicle having an input shaft connected to an internal combustion engine mounted on the vehicle and an output shaft connected to driven wheels of the vehicle, the transmission transmitting output torque generated by the engine to the driven wheels through the output shaft, comprising:

  • operating condition detecting means for detecting operating conditions of the engine and the vehicle including at least a vehicle speed and a throttle opening;

    grade parameter determining means for determining a grade parameter indicative of upgrade or downgrade of a road on which the vehicle runs, the grade parameter being calculated by the grade parameter determining means based upon a calculated actual vehicle acceleration and a predetermined predicted vehicle acceleration obtained from the detected operation conditions;

    shift program selecting means for selecting one from among a plurality of shift programs based on the determined grade parameter to determine a gear ratio based on the selected shift program;

    road information outputting means for determining an instantaneous vehicle position and for outputting road information including that at the determined instantaneous vehicle position;

    specific road determining means for determining whether the vehicle runs on a specific road including an upgrade/downgrade road based on the outputted road information;

    grade parameter comparing means for comparing the grade parameter with a threshold value; and

    grade parameter correcting means for correcting the grade parameter to increase the grade parameter when the grade parameter is greater or equal to the threshold value when the vehicle is determined to run on the specific road;

    wherein the shift program selecting means selects the one from among a plurality of shift programs based on the corrected grade parameters to determine the gear ratio based on the selected shift program.

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