Loading patent…
AssigneeJ. I. Case Company
InventorsKevin L. Brekkestran, John C. Thomas
Estimating the term…
A microprocessor-based electronic control system for a powershift transmission having at least one proportional actuator, such as a solenoid-operated proportional valve, is disclosed. The controller operates a plurality of on-off solenoid valves and solenoid-operated proportional valve to provide operator-selected gear shifts in both forward and reverse directions having controlled clutch engagements achieved by modulation of clutch engagement pressure by the proportional valve. The key parameters associated with the gradual clutch engagement are all easily varied by the controller, most under program control during operation, to provide for optimized clutch engagements for smooth gearshifts. The key parameters include: fast-fill clutch delay, initial clutch engagement pressure, rate of increase of clutch engagement pressure, and the length of the reduced pressure clutch engagement interval. The electronic controller also automatically modifies selected parameters in accordance with sensed changes in temperature, magnetic flux coupling between solenoids, and variations in the voltage supply provided to the series combination of the solenoid coil of proportional valve and its solenoid driver circuit. Preferred methods of operating the electronic controller and powershift transmission are also disclosed.
In a powershift transmission having a plurality of hydraulically-actuated clutches and a plurality of electronically-operated hydraulic valve means for selecting the clutches, with each such valve means including a solenoid coil to operate the valve, an electronic control system for compensating for the effect of magnetic coupling between at least two of the solenoid coils of the transmission, said control system including microprocessor means having memory means for program storage and for operating the powershift transmission in accordance with operating parameters stored in the memory means for:
A method of operating a power-transmitting apparatus having at least a plurality of actuator means for adjusting operating conditions of the apparatus, each of said actuator means including electrical coil means for operating the actuator means, the method comprising the steps of:
In an apparatus having a plurality of actuator means for adjusting operating conditions of the apparatus, each of the actuator means including a solenoid coil, an electronic control system for compensating the magnetic flux coupling between at least two of the solenoid coils of the apparatus, the control system including microprocessor means having memory means for program storage and for operating the apparatus in accordance with operating parameters stored in the memory means for
Dependencies are inferred from the claim text.