According to TRW, the motor pump unit delivers enhanced performance and environmental attributes when compared with conventional hydraulic solutions. With the motor pump unit, hydraulic assist is determined by the pump speed and controlled by a brushless motor which provides assist only when it is needed.

The system used on the various Mercedes models uses TRW's newest motor pump assembly providing a hydraulic output power of up to 1,000W. Compared with traditional hydraulic power steering, the system is claimed to offer fuel savings of up to 0.29L/100km and a reduction of CO2 emissions of approximately 6g/km.

TRW has said that its motor pump unit provides flexible tuning capability allowing the system to adapt to different driving conditions, providing a comfortable setting for parking and city driving, while delivering a safe feel at higher speeds.

There is also the option for electrically powered hydraulic steering system to vary assist levels depending on the vehicle loading information provided by other vehicle subsystems.

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