Mobility Solutions

Busworld Kortrijk 2015 Bosch presents smart, energy-saving steering systems

  • Servotwin® steering system supports implementation of assistance functions
  • New rear-axle steering system is considerably more efficient
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  • October 14, 2015
  • Mobility Solutions
  • Press releases
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press release

Efficiency and driver assistance are aspects that are currently attracting a great deal of interest in the commercial vehicle sector. Bosch is applying its extensive steering systems expertise in the passenger car segment to commercial vehicles. These innovations enhance safety and convenience in buses and significantly reduce fuel consumption and CO2 emissions. The Servotwin is the world’s first integrated electro-hydraulic steering system for production vehicles in the heavy commercial segment. This steering system with superimposed torque offers a great many benefits in buses too. The basic version provides speed-sensitive steering assistance and an active return to the straight-ahead position. The new-generation Servotwin additionally supports the implementation of driver assistance functions, which enhance safety and convenience in commercial vehicles. The Servotwin constitutes the core component in such assistance technologies.

Electronic assistance in buses
The lane keeping function prevents the vehicle from inadvertently wandering out of the lane by means of either corrective steering intervention or a warning signal. But that is not all: there is also an assistance function that eases the driver’s workload in traffic jams and stop-and-go traffic. In this case, the system maintains a set distance to the traffic ahead. The driver monitors the system and can override it, taking control at any time. Crosswinds pose a serious risk to heavy commercial vehicles due to their large surface area. To counteract the adverse effects of such suddenly occurring winds, a dedicated assistance function offsets the wind forces. In such situations, the steering system's control unit determines the steering correction needed and applies it via the electric motor. In addition to these benefits, the Servotwin steering system also has a positive effect on the commercial vehicle's efficiency. Depending on the driving cycle, Servotwin achieves a fuel saving of around 0.6 l/100 km compared with a conventional steering system.

Smart rear-axle steering system
The rear axle steering system (eRAS) has been completely redesigned and is now electronically controlled and electrically driven. As a result, the new eRAS features a power-on-demand function, so energy is only required when the steering is actually being used. The electric motor drives a pump that generates hydraulic pressure via an operating cylinder that is transferred to the rear axle. This on-demand provisioning of the steering power allows fuel savings of around 0.6 l/100 km to be achieved. The eRAS requires neither a mechanical nor hydraulic connection between the front and rear axle. This makes the system equally suited to volume-production integration and retrofitting. All the important geometric parameters, such as wheelbase and steering angle, are individually programmed in the steering control unit. Particularly buses with a large wheelbase benefit from smart rear-axle steering. Firstly, it reduces the bus’s turning circle – an advantage that especially becomes apparent in urban environments. Secondly, the eRAS increases vehicle stability and driving safety at higher speeds, for instance, during lane changing. Both Bosch systems enhance safety and convenience while at the same time considerably reducing the fuel consumption of commercial vehicles.

Contact person for press inquiries:
Götz Klausenburger
Phone: +49 7171 31-7625

Mobility Solutions is the largest Bosch Group business sector. In 2015, its sales came to 41.7 billion euros, or 59 percent of total group sales. This makes the Bosch Group one of the leading automotive suppliers. The Mobility Solutions business sector combines the group’s expertise in three mobility domains – automation, electrification, and connectivity – and offers its customers integrated mobility solutions. Its main areas of activity are injection technology and powertrain peripherals for internal-combustion engines, diverse solutions for powertrain electrification, vehicle safety systems, driver-assistance and automated functions, technology for user-friendly infotainment as well as vehicle-to-vehicle and vehicle-to-infrastructure communication, repair-shop concepts, and technology and services for the automotive aftermarket. Bosch is synonymous with important automotive innovations, such as electronic engine management, the ESP anti-skid system, and common-rail diesel technology.

The Bosch Group is a leading global supplier of technology and services. It employs roughly 375,000 associates worldwide (as of December 31, 2015). The company generated sales of 70.6 billion euros in 2015. Its operations are divided into four business sectors: Mobility Solutions, Industrial Technology, Consumer Goods, and Energy and Building Technology. The Bosch Group comprises Robert Bosch GmbH and its roughly 440 subsidiaries and regional companies in some 60 countries. Including sales and service partners, Bosch’s global manufacturing and sales network covers some 150 countries. The basis for the company’s future growth is its innovative strength. Bosch employs 55,800 associates in research and development at 118 locations across the globe. The Bosch Group’s strategic objective is to deliver innovations for a connected life. Bosch improves quality of life worldwide with products and services that are innovative and spark enthusiasm. In short, Bosch creates technology that is “Invented for life.”

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PI9080 - October 14, 2015

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