Patent ID: 8347618

Claim:
A hydraulic system for a vehicle driven by an internal combustion engine, comprising: a first higher pressure hydraulic system comprising a first hydraulic subsystem and a second hydraulic subsystem; a second lower pressure hydraulic system comprising a third hydraulic subsystem; a first pump supplying hydraulic fluid to the first hydraulic; system at said higher pressure; a second pump normally supplying hydraulic fluid to the second system at a lower pressure; a first valve having an inlet connected to the first pump and an outlet connected to the second subsystem, the first valve being operable to control communication between the first pump and the second subsystem; a second valve having an inlet connected to the second pump, a first outlet connected to the first subsystem and a second outlet connected to the second system, the second valve normally being in a first position wherein its second outlet is blocked and its inlet is connected to the first outlet, and the second valve being movable to a second position wherein its inlet is connected to its first and second outlets, the second valve comprises a pilot operated boost valve movable to an open position in response to pressure in a pilot line; and a solenoid operated pilot valve controls pressure in the pilot line.