A series hydraulic hybrid drive train for application in a passenger car is described. This ‘Hydrid’ drive train features an in-wheel hydraulic motor in all four wheels, hydraulic transformers for power control and hydraulic-pneumatic accumulators for energy storage and power management. The hydrostatic components are based on the highly efficient floating cup principle. The result is an efficient all-wheel drive vehicle with variable traction control on the front and rear axis.
The fuel economy and the CO2-emission of the drive train are calculated for a mid-class sedan while driving the New European Driving Cycle (NEDC). The efficiency of the hydrostatic components is derived from efficiency measurements of the floating cup pump.