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Through a series of incremental innovations, load sensing (LS) has become the current state-of-the-art in hydrostatic transmission technology. The Common Pressure Rail (CPR) is an alternative way to create a hydrostatic transmission. Although CPR systems offer considerable advantages over LS systems, they never really broke through. The main reason for this was the lack of a good solution to drive linear loads from a common pressure rail. The Innas Hydraulic Transformer (IHT) has been developed to fill this gap. It is a young component but has matured to a stage where a series production within the next two years should be possible. Because of its simple construction, its dynamic capacity, its low control power requirement and its efficiency it can be used to control both linear and rotary loads from a common pressure rail. With the IHT, the potential of CPR systems can finally be unleashed.

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. KEY WORDS Series Hybrid Hydraulic Vehicle Efficiency NOMENCLATURE This demand cannot be ful filled with current electric components [5]. Furthermore the electric transmission will substantially increase the weight and the cost of the transmission if the vehicle performance is not to be compromised.

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