...plus hy­brid up­date

New sys­tems in de­vel­op­ment Likely to fea­ture in Golf Mk8

Auto Express - - Contents - John Mcil­roy John_m­cil­roy@den­nis.co.uk @john­m­cil­roy

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

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