Patent ID: 7100723

Claim:
A method for controlling pressure in a hydraulic system that includes an engine, a pump driven by the engine for supplying fluid to a hydraulic rail, first and second pump-motors supplied with fluid through the rail for driving a load, a main accumulator connected to the rail and containing fluid at a first pressure, a power mode accumulator connected to the rail and containing fluid, and a low pressure accumulator, comprising the steps of: communicating the low pressure accumulator with a low pressure outlet of the pump-motors; monitoring a demand for an increase in a target parameter of the system; closing communication between the main accumulator and the rail after the demand occurs and before the target parameter is produced; adjusting a rate of fluid flow supplied by the pump to the rail such that a combination of pressure in the rail and a rate of fluid flow to the pump-motors produces the target parameter; and opening communication through the rail between the power mode accumulator and high pressure inlet of at least one pump-motor.