The current, two-door, two-seat model is in limited production, but Autocar understands that VW bosses are now considering building a second version that will accommodate four adults.
Ferdinand Piech, the chairman of the Volkswagen Group supervisory board, instigated the project to build a car that was capable of travelling 100km (62 miles) on one litre of fuel. That has culminated in the production version of the XL1, which is officially rated at 310mpg.
It is said that Piech is very keen to see VW remain at the cutting edge of what the company calls ‘super-efficient vehicles’ and wants to take the concept a step further, especially with the super-aero Honda FCV fuel-cell car set to go on sale at the start of 2015.
According to sources, much of the XL1 technology will be carried over into a new car – particularly the front and rear subframes and suspension and braking systems – although the central body structure would have to be totally rethought.
The XL1’s carbon tub would have to be replaced from scratch, but the staggered seating would remain because this is an essential element of keeping the car narrow and reducing its frontal area.
The new model – possibly called XL2 – would have to have two rear doors, which would most likely be rear-hinged like those on the BMW i3.
It is also likely that the current 800cc twin-cylinder diesel engine (which delivers 47bhp) and the electric motor (27bhp) would have to be upgraded with more power, although VW would aim to retain the same overall efficiency. The 5.5kWh lithium-ion battery would also probably be enlarged.