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US 11,493,127 B2Granted
System and method for reducing gear lash related torque disturbances
AssigneeFord Global Technologies, LLC
InventorsWeitian Chen, Matthew John Shelton, Zhengyu Dai, Pinzhi Liu, Jose Velazquez Alcantar, Joseph Jay Torres
Life of this patent
Estimating the term…
Abstract
Methods and system are described for changing a driveline gear range from a lower gear range to a higher gear range. The driveline may include two electric machines and four clutches in a four wheel drive configuration. The methods and systems permit a driveline to change from a lower gear range to a higher gear range in a way that may reduce torque disturbances that may result from gear lash.
Claims20
A method for operating a vehicle, comprising:
- shifting a first axle from a low gear range to a high gear range while meeting driver demand torque via a second axle, the shifting including ramping down torque of an electric machine of the first axle to first threshold positive torque, disengaging the low gear range, adjusting torque of the electric machine of the first axle to a negative torque in a predetermined amount of time after the electric machine of the first axle reaches the first threshold positive torque, the torque of the electric machine of the first axle adjusting a high gear range clutch's slip speed of the first axle, engaging a synchronizer in response to the high gear range clutch's slip is within a threshold of zero slip, closing the high gear range clutch, and increasing torque of the electric machine after closing the high gear range clutch.
A vehicle system, comprising:
- a first electric machine coupled to a front axle, the front axle including a first gearbox including a first gear and a second gear;
- a second electric machine coupled to a rear axle, the rear axle including a second gearbox including a third gear and a fourth gear;
- a controller including executable instructions stored in non-transitory memory to decrease output of the first electric machine to a negative torque and increase output of the second electric machine in response to a request to switch a driveline from a lower gear range to a higher gear range.
A method for operating a vehicle, comprising:
- shifting a first axle from a low gear range to a high gear range while generating a driver demand torque via a second axle, the shifting including ramping down torque of an electric machine of the first axle to a first threshold positive torque, disengaging the low gear range, adjusting torque of the electric machine of the first axle to a negative torque in a predetermined amount of time after the electric machine of the first axle reaches the first threshold positive torque, operating the electric machine of the first axle in a speed control mode in response to reaching the negative torque or a slip amount of a clutch of the first axle being less than a threshold, engaging a synchronizer in response to the slip amount is within a threshold of zero slip, closing the clutch, and increasing torque of the electric machine of the first axle after closing the clutch of the first axle.
Dependencies are inferred from the claim text.