×

Automatic transmission control system

  • US 4,779,491 A
  • Filed: 03/24/1987
  • Issued: 10/25/1988
  • Est. Priority Date: 03/25/1986
  • Status: Expired due to Term
First Claim
Patent Images

1. An automatic transmission control system for controlling an automatic transmission comprising a torque convertor having an input member connected to the engine output shaft and an output member connected to a multiple stage transmission gear mechanism adapted to provide a plurality of gear speeds, and a shifting means for shifting the gear speed, the shifting means having a plurality of frictional members, a plurality of hydraulic actuators for actuating the frictional members and a plurality of valve means which are controlled according to the vehicle operating condition to control application of hydraulic pressure from a hydraulic pressure source to the hydraulic actuators, said shifting means being adapted to shift the gear speed at least among a low gear speed, an intermediate gear speed and a high gear speed, a predetermined one frictional member out of said plurality of frictional members being released in the low gear speed and the high gear speed and engaged in the intermediate gear speed, and the predetermined one frictional member being engaged and released by a predetermined one hydraulic actuator out of said plurality of hydraulic actuators,wherein the improvement comprises a first control means which limits application of the hydraulic pressure to said predetermined one hydraulic actuator so that the hydraulic pressure is gently applied to the predetermined one hydraulic actuator upon upshift from the low gear speed to the intermediate gear speed, and a second control means which operates upon downshift from the high gear speed to the intermediate gear speed to nullify the limitation of application of the hydraulic pressure to said predetermined one hydraulic actuator.

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