Behind the wheel: Shell Concept Car​

If you’re interested in the future of motoring, you’re sure to be aware of Gordon Murray’s revolutionary iStream manufacturing process and the T25 prototype he built from it.

You probably also know that the T25 has recently become the Shell Concept Car. This is a three-seater with a 660cc petrol engine driving its rear wheels from beneath its boot.

The engine is based on a Mitsubishi design but has been reworked for maximum efficiency. The result is a car that moves efficiency to a whole new level – it’s not a hybrid, but it does 107mpg and CO2 emissions are miniscule. It’s designed to use the minimum of energy during manufacture, too.

How does a petrol-powered car use so little fuel? One reason is that it weighs only 500kg, another that its shape slips through the air with minimal drag.

What you don’t see, meanwhile, is that Shell has contributed its lubrication expertise to reduce friction in the engine, gearbox and wheel bearings. The company explains that in an average car, about 20% of the fuel you burn goes on overcoming friction – but that by using special lubricants this can be slimmed down to 15%. That might not sound like much, but it’s massive.

These lubes haven’t been offered for consumer sale, as they eat into the margin of error oil companies allow when developing such products. But Shell is confident that the gains seen in its concept can be translated into production reality.

Talking to Gordon Murray about this second lease of life for the T25, he admits to being surprised at how much weight and drag his company managed to trim off after Shell became involved in the project. ‘We thought we’d achieved a lot,’ he says. ‘But we’re now at a place we’d never have reached in one step.’

True to form, then, he confesses that even now, there’s more to be done to refine the engine’s efficiency. When it’s finally running perfectly, he believes its fuel efficiency will improve by something in the region of 3mpg.