Clutch and torque converter control for a continuously variable transmission

A hydraulic control system for a powertrain in a motor vehicle, the powertrain having a torque converter with a torque converter clutch (TCC) connectable with a continuously variable transmission, the transmission having a forward clutch and a reverse clutch, the hydraulic control system comprising:

• a pressure regulator subsystem providing a pressurized hydraulic fluid;
• a cooler subsystem for reducing a temperature of the pressurized hydraulic fluid;
• a manual valve assembly configured to selectively communicate the pressurized hydraulic fluid to the forward clutch and the reverse clutch;
• a torque converter control valve assembly having a first feed inlet, a second feed inlet connected to the pressure regulator subsystem, an apply port connected to an apply side of the TCC, a release port connected to a release side of the TCC, a cooler port connected to the cooler subsystem, and a failsafe port, and wherein the torque converter control valve assembly includes a control valve moveable between an apply position where the first feed inlet communicates with the apply port, and a release position where the second feed inlet communicates with the release port and the apply port communicates with the cooler port;
• a boost valve assembly having a first inlet port connected with the pressure regulator subsystem, a second inlet port connected with the pressure regulator subsystem, a manual valve outlet port connected with the manual valve, and a failsafe port connected to the failsafe port of the torque converter control valve assembly, and wherein the boost valve assembly includes a boost valve moveable between a boost position where the first inlet port communicates with the manual valve outlet port and a failsafe position where the second inlet port communicates with the failsafe port;
• a clutch control solenoid configured to move the boost valve to the boost position and the control valve to the release position and to control a pressure of the hydraulic fluid provided to the manual valve assembly;
• and
• a TCC control solenoid configured to move the boost valve to the boost position and to control a pressure of the hydraulic fluid provided to the torque converter control valve assembly.