Patent ID: 7972239

Claim:
An improved machine for hybrid drive operation having a primary power source and an alternative power source, both power sources being coupled to a machine propulsion means via a hydraulic transmission operated via a plurality of hydraulic clutches, the machine comprising: a primary hydraulic pump linked to the primary power source such that the primary hydraulic pump is driven by the primary power source, the primary hydraulic pump being fluidly connected to the hydraulic transmission to supply pressurized hydraulic fluid to the transmission for shifting and lubrication; a secondary hydraulic pump, the secondary hydraulic pump also being fluidly connected to the hydraulic transmission to supply pressurized hydraulic fluid to the transmission for shifting and lubrication; a pump motor linked to the secondary hydraulic pump to drive the secondary hydraulic pump; and a pump motor controller adapted to direct the operation of the secondary hydraulic pump based on a three-dimensional map linking a desired pump speed to a two-dimensional variable array, whereby a combined output of the primary hydraulic pump and the secondary hydraulic pump meets a required transmission hydraulic fluid flow over an entire operating speed range of said transmission.