At this stage, it is not known whether the new petrol-electric range-extender will be offered as an alternative to the existing plug-in hybrid drivetrain used by the X5 xDrive45e or whether it will supplant it.
ZF’s newly developed range-extender architecture consists of two variants: the eRE and eRE+. The former combines an electric motor, planetary gearset and integrated converter. The latter adds a clutch and differential, enabling it to serve as both a generator and a secondary drive source. Output of the combustion engine ranges from 148bhp to 201bhp.
ZF’s eRE and eRE+ units can operate at peak efficiency, running the combustion engine only within its optimal rev range. This not only improves fuel economy but also reduces emissions and complexity, offering shorter development cycles and more affordable production than traditional hybrid set-ups.
BMW is expected to combine elements of the ZF system with its sixth-generation electric drivetrain, which uses an 800V electric architecture. A key part of the development has involved leveraging experience from the experimental iX5 Hydrogen programme.
Although hydrogen-powered, the iX5 employs a system that mirrors the REx format: a fuel cell acts as an on-board generator, producing electricity to charge a buffer battery that then powers the electric motor. The vehicle has no mechanical link between the power unit and driven wheels – a layout that BMW aims to replicate with its combustion-equipped range-extender.
