Transmission for a powertrain system

A powertrain system, comprising:

• an internal combustion engine rotatably coupled to an input member of a transmission device to transfer mechanical power to an output member;
• the internal combustion engine being controllable to one of an engine-on state or an engine-off state;
• the transmission device including the input member, a hydraulic pump, a hydraulic circuit, a clutch assembly for transferring torque between the input member and the output member;
• the hydraulic pump being a mechanically-driven hydraulic pump rotatably coupled to the input member, the hydraulic pump being fluidly connected to the hydraulic circuit;
• the clutch assembly including a friction clutch pack, a clutch-apply piston, a clutch-release piston and a first spring;
• the clutch-release piston being fluidly coupled to a first hydraulic chamber that is fluidly coupled to the hydraulic circuit;
• the clutch-apply piston being fluidly coupled to a second hydraulic chamber that is selectively fluidly coupled to the hydraulic circuit;
• a second spring urging the clutch-apply piston;
• and
• the first spring urging the clutch-release piston.

A powertrain system, comprising:

• an internal combustion engine rotatably coupled to an input member of a transmission device to transfer mechanical power to an output member;
• the internal combustion engine being controllable to one of an engine-on state or an engine-off state;
• the transmission including the input member, a mechanically-driven hydraulic pump, a hydraulic circuit, and a clutch assembly for transferring torque between the input member and the output member;
• the mechanically-driven hydraulic pump being rotatably coupled to the input member and fluidly connected to the hydraulic circuit;
• the clutch assembly including a friction clutch pack, a clutch-apply piston, a clutch-release piston and a coned-disc spring;
• the clutch-release piston being fluidly coupled to a first hydraulic chamber that is fluidly coupled to the hydraulic circuit;
• the clutch-apply piston being fluidly coupled to a second hydraulic chamber that is selectively fluidly coupled to the hydraulic circuit;
• a second spring urging the clutch-apply piston;
• and
• the coned-disc spring urging the clutch-release piston;
• wherein when the internal combustion engine is in the engine-off state, the clutch assembly is activated by the coned-disc spring urging the clutch-release piston;
• wherein when the internal combustion engine is in the engine-on state and the transmission is commanded to a neutral state, the clutch assembly is deactivated;
• and
• wherein when the internal combustion engine is in the engine-on state and the transmission is commanded to a propulsion state, the clutch assembly is activated.