A system for a hydraulically driven vehicle includes an engine having multiple,
selectively operating cylinder-pump banks producing fluid flow at an outlet, a
pump/motor having a variable flow rate including an inlet for driving the wheels,
a hydraulic line having a line pressure and connecting the outlet and the inlet,
sensors producing signal representing line pressure, pump/motor speed, pump/motor
displacement, and a controller for determining a target hydraulic system parameter,
determining, based at least in part on the flow rate of the pump/motor and a flow
rate produced by each engine cylinder bank, a number of operating cylinder-pump
banks that is required to produce the target hydraulic system parameter, and in
response to determining the required number of operating cylinder-pump banks, adjusting
an engine operating parameter of a cylinder-pump bank such that the required number
of cylinder-pump banks operate.