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23.1.2009 BMW Hydrogen7 review

BMW Hydrogen7 review

Introduced at a time, when the motor industry is under intense pressure, you have to wonder about BMW's resolve with an H2-powered innovation. Iain Robertson provides a unique insight.

Liquid hydrogen is not a mass-market fuel. While the world motor industry is keen to drop us into compact, eco-friendly modes of transport, the hydrogen fuel cell remains a distant dream. Without a refuelling infrastructure, what is the point?

BMW feels the same way, yet has created 100 bi-fuel 760iL models, which would cost around $8m apiece, were you to buy one, to operate on hydrogen as well as gasoline. Not a unique proposition, as Mazda has produced a handful of RX8 sports prototypes that can run on liquid hydrogen, but only BMW has made its examples on a conventional production line.

Fuel cell vehicles operate on gaseous hydrogen. The liquid alternative demands storage at -253°C in a 170-litre double-skinned fuel tank, located above the rear axle. Of course, obtaining liquid hydrogen is fraught with difficulties but this car is `bi-fuel`. Powered by a 6.0-litre V12 petrol engine detuned from 455bhp to a diesel-like 260bhp, which makes the operational transition from petrol to hydrogen barely perceptible, with no loss of performance, and the overall innovation starts to make sense.

The hydrogen, fired by separate indirect-injection into the cylinders of the V12 engine, provides a range of around 240 kilometers, which works out to around 13.5l/100km economy. However, it emits zero pollution. Only pure water vapour emerges from its exhaust pipe. When the hydrogen is consumed, it runs on its other tank of conventional gasoline for a further 480 kilometers.

The Hydrogen7 drives conventionally. Refined, luxurious and comfortable, it suffers from the idiosyncrasies of the standard car…for that is what it is: a standard BMW 7-Series. With the notable exception that it can run on liquid hydrogen as a fuel source, which is the key thrust of this remarkable and groundbreaking machine. It is the extraordinary reduced to the ordinary. Because BMW is establishing the rules for a market that does not yet exist, whether we like it/believe it/want it or not, hydrogen is the future of clean and eco-friendly transport. BMW does it this way because conventional engineering is still available and still has a future.

BMW has won the international race to bring a H²-powered production model to market. The Hydrogen7 is a flag-bearer. However, developments continue apace and the next step is likely to be much smaller and no less conventional. Recent reports suggest that $1m will be required to establish each Hydrogen refuelling station to create a network. It is feasible. It is tenable. It is the future, albeit carrying today's hefty faux price-tag.

Iain Robertson © WhatGreenCar.com 2007

Posted by:
Ben Lane

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