German company ZF Friedrichshafen AG is using its plug-in Vision Zero concept vehicle to showcase a number of new safety and zero local emissions technologies. The vehicle features a 150 kilowatt electric axle drive system for dynamic acceleration. The entire propulsion system, including the integrated power electronics, is housed in a space saving modular ZF rear axle system called mSTARS (modular semi-trailing arm rear suspension).

This modular axle system makes it easier to electrify volume production vehicle platforms — even existing ones as demonstrated in the Vision Zero Vehicle. The system offers vehicle manufacturers the opportunity to respond to a diverse range of market requirements using just one car platform variant.The compact electric axle drive system is integrated into the mSTARS rear axle modular system. (Source:  ZF Friedrichshafen AG)The compact electric axle drive system is integrated into the mSTARS rear axle modular system. (Source: ZF Friedrichshafen AG)

The Vision Zero Vehicle is based on a volume production platform for compact and mid-size cars. The mSTARS semi-trailing link independent suspension takes up no more installation space than the conventional rear axle installed originally. The design frees up installation space between the rear wheels as a result of its unique integral link design and separate spring damper configuration. This means that ZF's electric drive fits effortlessly into the mSTARS system axle carrier.

The 150 kilowatt drive unit houses not only the electric motor but also a two-stage, one-speed spur gear drive, a differential, and power electronics along with control software.

The mSTARS axle also features a high level of driving dynamics and safety, delivering the performance of more expensive, conventional multi-link axles typically used for compact premium and sports vehicles. ZF’s AKC active rear axle steering system — which can be combined with any modular axle configuration — improves agility, comfort and stability. Since it also controls the rear wheel steering, it allows advanced assistance systems to operate more reliably and effectively.