...plus hybrid update
New systems in development Likely to feature in Golf Mk8
We try 48v ‘mild’ systems plus more powerful Golf GTE
BEFORE VW’S range of all-electric I.D cars hits showrooms in 2019, the German brand will roll out mild hybrid technology across its range of models.
The systems are expected to be offered first on the next generation of the Golf, and we’ve been to the company’s test facility in Germany to try out some prototypes.
There are two levels; the first VW calls MHEV (Mild Hybrid Electric Vehicle), which has a 48v-powered belt-driven starter-generator. The second, Mhevplus, adds an electric motor producing 25kw (34bhp) and a lithium-ion battery pack.
The combustion engine in both cases is the VW Group’s 148bhp 1.5-litre turbo petrol unit, as seen in the Golf. The transmission is the firm’s latest seven-speed DSG, which has been engineered to be compatible with the forthcoming hybrid systems.
VW laid out a simple course at its Ehra-lessein test track for us to sample the tech in prototypes based on the current Golf. The MHEV feels reassuringly simple and progressive to drive; there’s the smallest amount of electric whoosh as you pull away, just for a fraction of a second, as the 8kw starter-generator helps to get the wheels moving. Thereafter, it feels much like any other petrol Golf. VW estimates a potential gain of at least 7mpg in normal driving.
The more complex Mhevplus set-up has greater potential. Its electric motor can recuperate energy when braking without needing the petrol engine to be switched on, and it can drive the car on electricity alone.
The trade-off for these benefits is the fact that the tech is considerably more complicated. VW’S engineers admit they need to work hard on “mixing the torque” of the 25kw electric motor with the 1.5-litre engine’s contribution. And while the system is far from poor, there’s a noticeable series of transfers in the powertrain, as it mixes the ratio of electric to petrol power.
VW reckons that the Mhevplus tech could alternatively be used to power the rear wheels in slippery conditions, in a relatively simple all-wheel-drive configuration. This was demonstrated in a Tiguan stuck in sand and on a slippy gravel slope – and in both cases the 25kw electric motor was able to drive the rear wheels and get the car moving.
The mild hybrid systems – which will come in addition to the latest Mk7.5 Golf microhybrid that can deactivate the engine when you’re cruising – are part of VW’S ‘toolkit’ of new technologies to help meet CO2 targets.
ON TEST We tried out new 48v MHEV and Mhevplus tech at VW’S Ehra-lessein test facility FIRST DRIVE