×

Electronic system for controlling an automatic transmission in response to changes in slope

  • US 4,335,428 A
  • Filed: 01/24/1980
  • Issued: 06/15/1982
  • Est. Priority Date: 02/14/1979
  • Status: Expired due to Term
First Claim
Patent Images

1. A system for controlling an automatic variable speed transmission including a hydraulic circuit having a plurality of oil pressure control valves and flow path switching means for selectively engaging or disengaging clutches and brakes of the transmission, and a plurality of solenoid valves associated with a shift operation, said system comprising electronic control means responsive to shift lever position, vehicle speed and throttle opening, and having gear ratio change reference data for providing control signals to said solenoid valves to thereby control the operation of the transmission wherein:

  • said electronic control means includes memory means having shared therein slope detecting reference data indicative of the upper and the lower limit value of vehicle speed corresponding to a throttle opening for each of a selected number of slope running loadings and for each speed stage;

    gear ratio means for detecting and comparing the actual speed stage, the actual throttle opening, the actual speed of the vehicle and the change rate of the actual speed against said slope detecting reference data and means to modify the gear ratio change reference data to inhibit up-shifting on a slope to prevent hunting of gear ratios on an up slope and an undue need for braking on a down slope.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×