Engagement control having a multiplexed hydraulic circuit for controlling a torque converter clutch and shifting clutches in an automatic transmission

An electro-hydraulic control for a multi-ratio transmission, said transmission comprising a forward torque transmitting mechanism, a reverse torque transmitting mechanism and a torque converter clutch, said electro-hydraulic control comprising:

• a source of pressure;
• a variable output pressure solenoid valve having an inlet port communicating with said source of pressure and an output port;
• a torque converter clutch regulator valve having an inlet port communicated with said source, an output port, and a control port communicated with said variable pressure solenoid valve output port to control a variable pressure level at a said torque converter clutch regulator valve outlet port between a minimum and a maximum value;
• a torque transmitting mechanism regulating valve having an inlet port communicated with said source, a regulated outlet port, and a control port communicated with said variable pressure solenoid valve output port to control a variable pressure level at said torque transmitting mechanism regulator valve regulated outlet port between a minimum and a maximum value;
• and
• an engagement control valve having a torque converter clutch apply inlet port communicating with said torque converter clutch regulated outlet port, a torque converter clutch apply outlet port communicated with said torque converter clutch regulated outlet port, a torque transmitting mechanism inlet port communicated with said torque transmitting mechanism regulated outlet port, a torque transmitting mechanism outlet port communicated with a control for said forward and reverse torque transmitting mechanisms, a source inlet port, and control means for selectively positioning said engagement control valve in a first position to communicate said torque transmitting mechanism outlet port with said control for said torque transmitting mechanisms to provide pressure at a controlled rate to selectively apply one or the other of said torque transmitting mechanisms, and a second position to communicate said torque converter clutch apply outlet port with said torque converter clutch to provide an apply pressure thereto and to communicate said torque transmitting mechanism outlet port with said source to maintain said selected torque transmitting mechanism applied.