US Patent 7415820 Hybrid powertrain with valve assembly for dual pumps

A powertrain includes a first pump and a second pump. A conduit defines a passageway for providing hydraulic pressure from the first pump or the second pump to a transmission. A valve assembly is configured to selectively supply hydraulic pressure to the passageway solely from the first pump, solely from the second pump, and from both the first and second pumps. The valve assembly thus enables the first and second pump to augment one another, thereby enabling the size of at least one of the pumps to be smaller than would otherwise be possible without the valve assembly.