US Patent:
20190047568, Feb 14, 2019
Inventors:
- Dearborn MI, US
Ryan Eggebrecht - Merrill MI, US
Timothy Fedullo - Northville MI, US
Samuel Glauber - Northville MI, US
International Classification:
B60W 30/18
F16H 61/00
F16H 61/12
F16H 63/34
B60W 10/115
B60W 10/196
B60W 30/19
Abstract:
A transmission park mechanism is hydraulically actuated. Specifically. a controller releases the parking pawl by commanding engagement of particular shift elements at an elevated line pressure. The process of transitioning from Park to a Drive or Reverse condition may involve several sequential steps. To reduce the delay between driver selection of Drive or Reverse and completion of the engagement, it is advantageous to raise the line pressure in response to depression of a brake pedal, prior to movement of the shift lever. To limit the adverse fuel economy impact of increased line pressure, the line pressure is lowered again if the driver does not move the shift lever soon after depressing the brake pedal.