Abstract
As a joint venture of Robert Bosch GmbH and ZF Friedrichshafen AG, ZF Lenksysteme GmbH is one of the largest independent manufacturers in steering systems and system components. The steering system represents one of the most important functions in a vehicle. Here the driver still keeps his hands on and defines driving, means safety and comfort. Since the steering system could even characterize a vehicle, our products have been continuously improved and developed to fullfill specific vehicle requirements.
ZF Lenksysteme is also leading in the latest developments of electrical steering systems. This new steering system combines high comfort and precision with little energy consumption compared with present hydraulic systems. The steering systems in passenger cars are currently experiencing a changeover from the hydraulic assisted power steering gears towards electrical steering gears. In the next years to come, the hydraulic power steering system will, however, continue to be needed in particular on vehicles with high steering performances as these cannot be covered with the current electrical bordnet (12 V).
On the other hand, the OEMs are struggling to achieve the upcoming tightened limit values for exhaust emissions. Developments like direct gasoline injection, variable valve tuning, weight reductions, are just a few among others to achieve the future requirements. But also within the hydraulic steering system technology, solutions enabling a cutting-down of the energy consumptions are expected.
Taking the power steering pump as an example ZF Lenksysteme has started to develop solutions to achieve a reduction of up to 75 % in fuel consumption depending on driving conditions. As an average the current hydraulic steering system consumes 0,3 l / 100km depending on vehicle size, load cycle and steering system layout.