ZF’s latest range-extender systems, eRE and eRE+, are designed to speed up car makers’ evolution of hybrid and EV technology – and help them mould around increasingly tumultuous market conditions.

“It could potentially revitalise the somewhat sluggish electric vehicle market in Europe and the US,” says the company. “Major manufacturers like Hyundai, Ford and Stellantis are showing interest in range-extender technology and planning to launch vehicles equipped with it within the next two years.” Its halo gearbox certainly has a good track record of breaking down rivalries and supplying multiple, competing manufacturers all at once.

So what’s new compared with a decade ago? “When you look at the history of range-extenders, [engines] like those in the i3 were designed to help you in utmost urgency,” says ZF’s e-mobility R&D boss Otmar Scharrer. “This has changed. Range-extenders are now much stronger and more powerful.”

Cooling, packaging and refinement have improved as REx cars move away from shrunken engines to proven larger units with a strong, efficient mid-range and capable of running frequently rather than being dipped into sparingly. A naturally aspirated petrol four-pot is optimal.

While neither of ZF’s new offerings drives the wheels directly – it’s key to their MO – they can work with up to 200bhp of engine output and either plug and play with a manufacturer’s existing engine and motor or use a clutch and differential to create a more flexible set-up where an intermediary generator can drive the wheels. Both options can hook up to 400V or 800V charging architecture.