Regenerative torque limit control
A vehicle includes a powertrain and at least one controller programmed to, in response to a brake request and a shaft speed associated with a speed of the vehicle achieving a starting speed that is defined by a torque of the powertrain that changes with brake demand at a given shaft speed, reduce a regenerative torque limit that constrains regenerative braking torque over a blend-out duration based on the shaft speed.
1. A vehicle comprising:
a powertrain having a torque converter clutch; and
at least one controller programmed to in response to a brake request, specify a regenerative torque limit based on a shaft speed over a blend-out duration that ends with the clutch unlocking such that a regenerative braking torque applied by a traction motor following the regenerative torque limit decreases according to a blend-out rate that is based on a desired friction brake fill-in rate.
2. The vehicle of claim 1 , wherein the at least one controller is further configured to command a traction motor to apply the regenerative braking torque constrained by the regenerative torque limit over the blend-out duration.
3. The vehicle of claim 1 , wherein the blend-out duration begins when the shaft speed reaches a starting speed that is based on the blend-out rate and a torque of the powertrain at a given shaft speed.
4. The vehicle of claim 3 , wherein the torque of the powertrain changes with brake demand, a capacity of the powertrain, or a vehicle stability limit at a given shaft speed.