Electric powertrain and method of calibration
AssigneeCaterpillar Inc.
InventorsBrian E. Lister, Bernard M. Murphy
Life of this patent
Estimating the term…
Abstract
An electric powertrain includes a transmission connected with a traction motor to receive motive power embodied as torque and speed. To adjust the torque and speed, the transmission has a plurality of gear sets that are selectively engaged by actuation of associated hydraulic clutches. For actuation, the hydraulic clutches receive hydraulic fluid from a hydraulic system. To calibrate actuation of the clutches, the traction motor is run at a reduced speed range under calibration conditions while the hydraulic system is operated at a operational speed range. Further, a torque/current limit is applied to the traction motor to limit torque applied to the transmission during calibration.
Claims20
A method of calibrating a transmission for an electric powertrain comprising:
- running a traction motor in accordance with a reduced speed range to direct motive power to the transmission;
- running a hydraulic pump in accordance with an operational speed range to pressurize hydraulic fluid;
- applying an actuation current to a valve solenoid associated with a hydraulic valve to direct the hydraulic fluid to a clutch actuator and engage a hydraulic clutch;
- monitoring a transmission response variable;
- and
- correlating the transmission response variable with the actuation current.
An electric powertrain comprising:
- a transmission including a plurality of selectively engageable gear sets, a hydraulic clutch including a plurality of clutch plates engageable with each other, and clutch actuator configured to move the clutch plates into and out of engagement;
- a traction motor operatively connected to direct a motive force to the transmission, the traction motor including a motor controller configured to operate the traction motor at a reduced speed range;
- a hydraulic system including a hydraulic pump fluidly connected to a hydraulic valve fluidly connected to the clutch actuator to direct hydraulic fluid thereto, the hydraulic valve operatively associated with a valve solenoid;
- an electronic controller configured to apply an actuation current to the valve solenoid;
- to monitor transmission response variable, and to correlate the transmission response variable with the actuation current.
Dependencies are inferred from the claim text.