At last month’s LA Auto Show, Volkswagen’s luxury arm Audi unveiled a world-first: a performance plug-in hybrid with a hydrogen fuel cell rather than an internal combustion engine providing range-extending capabilities.
At the time, we said Audi’s A7 Sportback H-Tron Quattro was the most logical implementation of hydrogen fuel cell technology we’ve seen to date, combining the low running costs and zero-emissions capabilities of a plug-in vehicle with range-extending capabilities of hydrogen. Solving the problem of limited and costly hydrogen refuelling infrastructure while simultaneously solving the limited-range problem of traditional plug-in vehicles, the A7 Sportback H-Tron Quattro seemed to offer it all without any compromise. In short, it seemed a well engineered, expert solution.
But as Automotive News (subscription required) found out over the weekend, the real reason for Audi unveiling a plug-in hydrogen hybrid vehicle at the LA Auto Show while parent company Volkswagen stuck to a hydrogen-only vehicle doesn’t paint current hydrogen fuel cell technology in a positive light.
In the words of Dr. Prof. Ulrich Hackenberg, Audi’s research and development chief, the marriage of plug-in hybrid and hydrogen technologies was needed to “make it a proper Audi.”
Or to put it another way, the hydrogen fuel cell stack Audi had access to simply wasn’t powerful enough to give the Audi A7 Sportback H-Tron Quattro the kind of performance required of any vehicle wishing to wear the famous Quattro name plate.
On its own, the hydrogen fuel cell technology in the A7 Sportback H-Tron Quattro is capable of outputting just over 100 kilowatts of power — or 137 brake horsepower. Worse still, in its stock configuration as a hydrogen-only vehicle, only two wheels would have been driven, meaning Audi couldn’t have used the Quattro name.
Instead, Hackenberg explained, Audi engineers used the plug-in drivetrain found in Audi’s recently-launched A3 e-Tron Sportback, adding a second motor to drive the other axle and providing a combined power output of 170 kilowatts.
Producing more than 398 foot-pounds of torque, the two drivetrains work together to accelerate the A7 Sportback H-Tron Quattro from 0-62 mph in a much more respectable 7.9 seconds. For those taking notes, that’s hardly as quick as some Audi models — and in fact a similar speed to the BMW i3 REx — but considering its 4,299 pound kerb weight, that’s far better than it could have been.
Audi’s decision to use a plug-in hybrid hydrogen drivetrain not only casts doubt on the performance of other hydrogen fuel cell vehicles, but confirms what we’ve seen so far from any automaker dabbling in hydrogen fuel cell technology.
While hydrogen fuel cell stacks might make it possible to power a zero emission vehicle on compressed hydrogen and oxygen from the air we breathe, fuel cell stack development needs a major improvement in energy density before we see sporty, performance-oriented hydrogen fuel cell vehicles wooing the crowds at major auto shows.
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