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LA DEBUTS: Audi A7 h-tron - hydrogen fuel cell

By Glenn Brooks | 20 November 2014

Prototype based on just-facelifted A7

Prototype based on just-facelifted A7

Audi has revealed an experimental hydrogen fuel cell version of the A7 Sportback at the LA auto show. But there's a twist: it's also a plug-in hybrid.

The prototype is claimed to have a range of 500km or 310 miles and to emit only water. Indeed, the exhaust system is plastic for this reason. The car's power output is said to be 170kW and drive can go to all four wheels though there is no mechanical connection between the front and rear axles. Torque is distributed to the back wheels from a rear-mounted electric motor.

The car needs about one kilogram (2.2 lb) of hydrogen to cover 100 kilometres (62.1 mi), accoring to Audi. That energy content is equivalent to that of 3.7 litres (1.0 US gal) of gasoline.

As per cars with combustion engines, refueling takes no more than around three minutes. The range is boosted by up to 50km (31 miles) by a battery with a capacity of 8.8kW, which is recharged by recuperation or alternatively from a power socket. As a plug-in hybrid, the A7 Sportback h-tron quattro therefore has a crucial extra range in reserve.

Performance is good, if not spectacular. Top speed is just 180km/h (112mph) with 0-100km/h taking a stated 7.9 seconds.

The Volkswagen Group continues to maintain its long-held view that it wants to be ready with hydrogen-fuelled vehicles but that it prefers to wait for a refuelling infrastructure to be more extensively installed in key markets. Once this happens, the Group will then commit itself to series or even limited production of such models.