Automated transmission upshift control

  • US 6,149,545 A
  • Filed: 01/14/1999
  • Issued: 11/21/2000
  • Est. Priority Date: 01/14/1999
  • Status: Expired due to Term
First Claim
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1. A method for controlling automatic upshifting in a vehicular automated mechanical transmission system (10) for a vehicle comprising a fuel-controlled engine (12) having a maximum torque rotational speed, a multiple-speed mechanical transmission (14), and a controller (28) for receiving input signals (30) including one or more of signals indicative of engine speed (ES), engaged gear ratio (GR) and vehicle speed (OS), and to process said input signals in accordance with logic rules to issue command output signals (32) to transmission system actuators including a transmission actuator (52) effective to shift said transmission, said method characterized by:

  • (i) establishing a maximum acceptable time (TMAX) for completion of skip upshifts;

    (ii) establishing an upshift feasibility criteria whereby upshifts into a target gear ratio are considered feasible only if, under sensed vehicle operating conditions,(a) substantial synchronization can be obtained above a predetermined engine speed substantially equal to maximum torque rotational speed and(b) at engagement of the target ratio, the vehicle will be capable of at least a predetermined acceleration (dOS/dt);

    (iii) upon sensing a requirement (ES>

    ES/U/S) for an upshift from an engaged gear ratio (GR), in sequence;

    (a) determining if a skip upshift of two ratios from the currently engaged ratio (GRTARGET=GR+2) is feasible within a time no greater than said maximum acceptable time and, if so, commanding a skip upshift of two ratios from the currently engaged ratio;

    if not,(b) then determining if a single upshift (GRTARGET=GR+1) without using engine brakes is feasible and, if feasible, commanding a single upshift from the currently engaged ratio without using engine brakes.

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