What is it?
Volkswagen’s Golf 1.5 TSI MHEVs (mild hybrid electric vehicles) are engineering prototypes equipped with the firm's new 48V electrical systems, which are likely to become commonplace in the next couple of years.
The 48V systems are simple, mainly because, unlike a full hybrid or plug-in hybrid, they operate at low voltage, making them relatively cheap and easy for manufacturers to install.
They consist of a belt-integrated starter generator (BISG) and 48V lithium ion battery that's about the size of a conventional 12V battery. The 12V battery is retained to drive the conventional electrics and is charged from the 48V system. The BISG can boost acceleration, recover energy and store it in the lithium ion battery when the car slows or the brakes are applied. It makes stop-start much faster and smoother because of the extra power compared to a 12V starter system.
We briefly tried two versions, the Golf MHEV and Golf MHEV Plus, at Volkswagen's Ehra-Lessien proving grounds. The first is a straightforward front-wheel-drive Golf MHEV powered by a 148bhp 1.5-litre TSI turbocharged petrol engine, equipped with an 8bhp BISG and a prototype of the all-new DQ381 seven-speed DSG automatic transmission. The MHEV Plus has an additional 34bhp electric motor driving its front axle.