Deere + Company

Joel Lee Mason

Duane Fredrick Meyer

Bradley Allen Merrill

Daniel Avery Allen

Duane Frederick Meyer

A method is provided for shifting a powershift transmission in a vehicle having an electronic engine control unit and an electronic transmission control unit. The method rapidly reduces off-going clutch pressure to a pressure which is slightly higher than a Predicted Off Slip Pressure, and rapidly increases on-coming clutch pressure P-on to a pressure that is slightly lower than a Predicted On Slip Pressure. Then, the method includes gradually decreasing P-off and gradually increasing P-on until slipping of the off-going clutch is detected, and gradually and more slowly decreasing P-off and gradually more slowly increasing P-on until the oncoming clutch begins to carry torque previously carried by the off-going clutch. Finally, the method includes more rapidly decreasing P-off to reservoir pressure, and more rapidly increasing P-on to a full on pressure.

Transmission shift control method

A method is provided wherein when an auxiliary device is being powered by the PTO driveline the PTO clutch is periodically slowly ramped down in pressure until slippage is detected in the clutch. Slippage is determined by monitoring the shaft speed into the clutch as well as the shaft speed downstream of the clutch. By determining the commanded pressure where slippage occurred, the equivalent engine power that is going to the auxiliary function is calculated. With this information, the proportion of the engine load signal that is going to the auxiliary function versus the drive wheels is determined. After slip is detected in the PTO clutch, pressure is ramped back up in the clutch so as to minimize the amount of slippage.

Growing community of inventors

Cedar Falls, IA, United States of America

Joel Lee Mason