US 12,146,566 B1
Grade based transmission park pawl unloading via clutch activation
Corey Allard, Fenton, MI (US)
Assigned to FCA US LLC, Auburn Hills, MI (US)
Filed by FCA US LLC, Auburn Hills, MI (US)
Filed on Oct. 25, 2023, as Appl. No. 18/493,913.
Int. Cl. F16H 61/04 (2006.01); F16H 59/52 (2006.01); F16H 59/66 (2006.01)
CPC F16H 61/04 (2013.01) [F16H 59/52 (2013.01); F16H 59/66 (2013.01); F16H 2059/663 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A park control system for grade based transmission park pawl unloading of a vehicle, the park control system comprising:
a set of sensors configured to monitor a set of load parameters of the vehicle, the set of load parameters including at least a grade of a surface that the vehicle is on and a weight of the vehicle; and
a controller configured to:
detect a request to shift a transmission of the vehicle out of a park state where a park pawl is engaged with an output shaft of the transmission to inhibit or prevent vehicle movement;
in response to detecting the request, determine the set of load parameters using the set of sensors;
based on the set of load parameters, activate a series of a plurality of clutches of the transmission to cause the transmission to transfer or output a desired amount of drive torque in a desired direction to unload the park pawl; and
when the park pawl is unloaded, shift the transmission out of the park state without any noise/vibration/harshness (NVH) associated with a previous loading of the park pawl due to the surface grade and the vehicle weight.