Hydraulic control system for an automatic transmission

1. A hydraulic control system for a ten-speed automatic transmission, the hydraulic control system comprising:

a pressure regulator subsystem with a source of pressurized hydraulic fluid for providing a flow of hydraulic fluid;

an electronic transmission range selection (ETRS) control subsystem including a set of three valve assemblies, the ETRS control subsystem further including a Park mechanism that communicates with an out-of-Park solenoid and a Park servo valve; and

a clutch actuation control subsystem that provides pressurized hydraulic fluid to a plurality of clutch actuators through a plurality of clutch valve assemblies,

wherein the ETRS control subsystem connects the pressure regulator subsystem with the clutch control subsystem and wherein the ETRS control subsystem converts electronic input for a requested range selection into hydraulic and mechanical commands.

2. The hydraulic control system of claim 1 wherein the source of pressurized hydraulic fluid is a pump.

3. The hydraulic control system of claim 1 wherein the set of three valve assemblies of the ETRS control subsystem includes an enablement valve assembly, a first mode valve assembly, and a second mode valve assembly.

4. The hydraulic control system of claim 3 wherein the enablement valve assembly communicates with the first mode valve assembly and the second mode valve assembly.

5. The hydraulic control system of claim 1 wherein each of the valve assemblies of the ETRS control subsystem includes valves slidably disposed in a bore.

6. The hydraulic control system of claim 1 wherein the ETRS control subsystem further includes a spool valve assembly that communicates with the first mode valve assembly.

7. The hydraulic control system of claim 6 wherein the spool valves are slidably disposed in a bore.

8. The hydraulic control system of claim 1 wherein the plurality of clutch actuators includes six clutch actuators.

9. The hydraulic control system of claim 8 wherein each of the clutch actuators is a hydraulically actuated piston that engages one of a plurality of torque transmitting devices to achieve a desired speed ratio.

10. The hydraulic control system of claim 1 wherein each of the plurality of clutch actuators is activated by one of a plurality of variable force solenoids through the plurality of clutch valve assemblies.

11. The hydraulic control system of claim 1 wherein the out-of-Park solenoid is actuated to prevent the Park mechanism from engaging during an engine stop-start event.

12. The hydraulic control system of claim 1 wherein the out-of-Park solenoid disengages the Park servo valve to operate the transmission in Drive or Reverse.

13. A hydraulic control system for a ten-speed automatic transmission, the hydraulic control system comprising:

a pressure regulator subsystem with a source of pressurized hydraulic fluid for providing a flow of hydraulic fluid;

an electronic transmission range selection (ETRS) control subsystem including a set of three valve assemblies, the ETRS control subsystem further including a Park mechanism that communicates with an out-of-Park solenoid and a Park servo valve; and

a clutch actuation control subsystem that provides pressurized hydraulic fluid to a plurality of clutch actuators through a plurality of clutch valve assemblies, the clutch actuator control subsystem including a clutch select valve assembly that communicates with the pressure regulator subsystem,

wherein the ETRS control subsystem connects the pressure regulator subsystem with the clutch control subsystem and wherein the ETRS control subsystem converts electronic input for a requested range selection into hydraulic and mechanical commands.

14. The hydraulic control system of claim 13 wherein the set of three valve assemblies of the ETRS control subsystem includes an enablement valve assembly, a first mode valve assembly, and a second mode valve assembly.

15. The hydraulic control system of claim 13 wherein the plurality of clutch actuators includes six clutch actuators.

16. The hydraulic control system of claim 15 wherein each of the clutch actuators is a hydraulically actuated piston that engages one of a plurality of torque transmitting devices to achieve a desired speed ratio.