Method and apparatus for a transmission control system
Valve arrangement for closed-loop control system Patent #: 4116321
ApplicationNo. 06/064079 filed on 08/06/1979
US Classes:137/596.15, Common to plural valve motor chambers477/131Electric control
ExaminersPrimary: Husar, C. J.
Assistant: McKenzie, Frank
Attorney, Agent or Firm
International ClassF16H 61/02 (20060101)
AbstractA hydraulic control for an automatic transmission has a plurality of shift control valves for controlling the interchange of drive ratios within the transmission. The shift control valves each have a control chamber subjected to substantially constant pressure and a shift control chamber having an area proportional to the respective control chamber which is subjected to a variable control pressure. The variable control pressure is controlled at discrete levels by a single pulse width modulator (PWM) solenoid. The respective area ratios of the shift control chambers to the controlled chambers determines the distinct shift point of each shift valve.