Hydraulic control system for an automatic transmission having analog electronic transmission range selection

摘要

A hydraulic control system for a transmission includes a source of pressurized hydraulic fluid that communicates with an electronic transmission range selection (ETRS) subsystem. The ETRS subsystem includes an ETRS valve, a park mechanism, a mode valve, a latch valve assembly, and a plurality of solenoids. The ETRS subsystem is configured to provide desired operating conditions during a plurality of potential failure conditions.

主权项

1. A hydraulic control system for a transmission, the transmission having a Park mode and an Out of Park mode of operation, the transmission having a plurality of torque transmitting devices selectively engageable to provide at least one forward speed ratio and at least one reverse speed ratio when in the Out of Park mode of operation, the hydraulic control system comprising:
a pressure regulator subsystem for providing a pressurized hydraulic fluid; a clutch actuator subsystem for selectively actuating the torque transmitting devices upon receipt of the pressurized hydraulic fluid; a manual valve assembly in downstream fluid communication with the pressure regulator subsystem and in upstream fluid communication with the clutch actuator subsystem, the manual valve assembly having a manual valve moveable between a Park position and an Out of Park position; a detent mechanism connected to the manual valve, wherein the detent mechanism detents the manual valve into the Out of Park position; a latch valve assembly in downstream fluid communication with the pressure regulator subsystem and the manual valve assembly, the latch valve assembly having a latch valve moveable between a Park position and an Out of Park position; a park servo in downstream fluid communication with the latch valve assembly and the manual valve assembly; and a park lock mechanism mechanically coupled to the park servo, wherein the park servo mechanically moves the park lock mechanism to place the transmission in the Park condition when the manual valve and the latch valve are in the Park positions and wherein the park servo mechanically moves the park lock mechanism to place the transmission in the Out of Park condition when the manual valve and the latch valve are in the Out of Park positions.