Hydraulic system with smart relief valve and valve control method

A method for operation of a transmission system, comprising:

• actively adjusting a position of a relief valve based on an aggregate hydraulic pressure demand of a plurality of hydraulic devices to alter a boost pressure of a hydraulic fluid supplied to a plurality of control valves;
• and
• during an engine cranking event, operating the relief valve to decrease the boost pressure to a lower pressure;
• wherein the transmission system includes:
• a boost pump;
• the relief valve in fluidic communication with the boost pump and a reservoir;
• and
• the plurality of control valves in fluidic communication with the boost pump, positioned downstream of the relief valve, and in fluidic communication with the plurality of hydraulic devices.

A hydromechanical variable transmission (HVT) system, comprising:

• a hydraulic pump;
• a relief valve in fluidic communication with the hydraulic pump and a reservoir;
• a plurality of control valves in fluidic communication with the hydraulic pump, positioned downstream of the relief valve, and in fluidic communication with a hydraulic clutch and a hydrostatic pump;
• and
• a controller including instructions that when executed, during transmission operation, cause the controller to:
• determine an aggregate hydraulic pressure demand of the hydraulic clutch and the hydrostatic pump;
• and
• actively adjust a position of the relief valve based on the aggregate hydraulic pressure demand to augment a boost pressure of a hydraulic fluid supplied to the plurality of control valves.