Valentin Technologies, Inc. was a Wisconsin-based developer of hydrostatic (hydraulic) drivetrain concepts that promoted an experimental hydraulic-hybrid passenger-car program called the INGOCAR, presented as a mid-size, five-seat vehicle built around an engine-driven hydraulic pump, a pressurized accumulator for energy storage, and hydraulic wheel motors that also provided regenerative braking by pumping energy back into the accumulator. The…