Torque converter lockup clutch slip control
AssigneeAllison Transmission, Inc.
InventorsJohn Byerly, Jeff Shultz
Life of this patent
Estimating the term…
Abstract
A method and system are provided for operating a lockup clutch of a torque converter of a motor vehicle. The torque converter includes a pump rotatably driven by a drive unit, a rotatable turbine fluidly coupled to the pump and configured to drive an input shaft of a transmission, and a lockup clutch selectively engageable to non-fluidically couple the pump to the turbine to transmit torque from the drive unit to the transmission. The operation of the lockup clutch is controlled by the system in response to detecting that the motor vehicle is coasting.
Claims20
A system for a vehicle, the system comprising:
- a drive unit configured to output torque, the drive unit including an output shaft,
- a transmission configured to transmit torque output by the drive unit to a load, the transmission including an input shaft,
- a torque converter coupled between the drive unit and the transmission, the torque converter including a pump coupled to the output shaft of the drive unit, a turbine coupled to the input shaft of the transmission, a lockup clutch selectively engageable to mechanically couple the pump to the turbine to transmit torque between the drive unit and the transmission;
- and
- a torque converter controller having a processor and memory, the memory having instructions stored therein that are executable by the processor to cause the processor to (i) determine whether the vehicle is in a coasting condition, (ii) determine whether a rotational speed of the output shaft of the drive unit has reached a target speed above a reference threshold, and (iii) engage the lockup clutch to maintain the rotational speed of the output shaft above the reference threshold in response to a determination that the motor vehicle is in the coasting condition and that the rotational speed of the output shaft has reached the target speed.
A control system for a vehicle, the vehicle including a drive unit, a transmission, and a torque converter having a lockup clutch selectively engageable to mechanically couple a pump of the torque converter to a turbine of the torque converter, the control system comprising:
- a plurality of sensors configured to produce sensor data, wherein the sensor data is cooperatively indicative of a coasting condition of the vehicle;
- a drive unit speed sensor configured to provide a signal indicative of a rotational speed of an output shaft of the drive unit, and
- a torque converter controller coupled to each of the plurality of sensors and the drive unit speed sensor, the torque converter controller including a processor and memory, the memory having instructions stored therein that are executable by the processor to cause the processor to (i) determine whether the vehicle is in the coasting condition based on the sensor data produced by the plurality of sensors, (ii) determine whether the rotational speed of the output shaft of the drive unit has reached a target speed above a reference threshold based on the signal from the drive unit speed sensor, and (iii) engage the lockup clutch to maintain the rotational speed of the output shaft above the reference threshold in response to a determination that the vehicle is in the coasting condition and that the rotational speed of the output shaft has reached the target speed.
A method of operating a vehicle, the vehicle including a drive unit, a transmission, and a torque converter having a lockup clutch selectively engageable to mechanically couple a pump of the torque converter to a turbine of the torque converter, the method executable by a torque converter controller of the torque converter, the method comprising:
- determining, based on sensor data from a plurality of sensors, whether the vehicle is in a coasting condition,
- determining, based on a signal provided by a drive unit speed sensor, whether a rotational speed of an output shaft of the drive unit has reached a target speed above a reference threshold, and
- engaging the lockup clutch to maintain the rotational speed of the output shaft above the reference threshold in response to a determination that the vehicle is in the coasting condition and that the rotational speed of the output shaft has reached the target speed.
Dependencies are inferred from the claim text.