Transmission engagement control system

The invention discloses a transmission engagement control system. A transmission park mechanism is hydraulically actuated. Specifically. a controller releases the parking pawl by commanding engagementof 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. 本发明公开种变速器接合控制系统。变速器驻车机构是液压致动的。具体地，控制器通过在升高的管路压力下控制特定换挡元件的接合而释放所述驻车棘爪。从驻车挡状态到前进挡或倒车挡状态的转换的过程可包括多个顺序的步骤。为了降低在驾驶员选择的前进挡或倒车挡和完成所述接合之间的延迟，在换挡杆移动之前响应于制动踏板的踩下而升高所述管路压力是有益的。为了限制增加的管路压力对燃料经济性的负面影响，如果在踩下制动踏板后驾驶员没有马上移动换挡杆，则管路压力再次降低。