Lean, green eco machines

1/2
10 April 2012

It's easy to get gloomy about motoring nowadays: fuel prices are shockingly high while, for many, VED, insurance rates - and of course congestion - have soared. But there is good motoring news too, and there's a new car magazine dedicated to it, claiming to be the "definitive guide to the most efficient and intelligent cars you can buy today".

iCAR is about cars that enhance your life without spoiling everyone else's, and the magazine has looked into which is the most cost-effective and
climate-friendly hybrid or economical diesel. Its findings are highly instructive. The best-known hybrid is the Toyota Prius. The first really
successful hybrid car, says iCAR, it also remains one of the best, thanks to its advanced petrol-electric powertrain.

Highlights include a 1.8-litre petrol engine with nickel-metal hydride (NiMH) battery pack, electric motor and automatic transmission, giving 89g/km and 72.4mpg on the combined cycle. Slipping under the 100g/km barrier ensures the Prius is exempt from the London congestion charge, also qualifying for free road tax and the lowest rates of company car tax.

Hybrids, iCAR points out, are at their best in urban motoring conditions. The key with the Prius is a combination of stop-start technology, brake energy regeneration and battery power. Put them all together and you have a car that operates its engine only when necessary, recaptures energy on the move and is capable of running in
pure-electric mode with zero tailpipe emissions. Perfect for negotiating rush-hour London.

"Open the taps out of town, however, and the Prius and other current hybrids aren't so convincing," says motoring expert Jeremy Laird, editor of iCar magazine. "Free-flowing traffic requires constant power from the petrol engine and reduces the hybrid kit to dead weight."

Enter, therefore, the long-distance diesel. BMW's 320d EfficientDynamics isn't the most efficient oil burner you can buy, but the magazine
report describes it as a "superb all-rounder and a great example of the state of the art in diesel technology".

The 320d EfficientDynamics shares several fuel-saving features with the Prius, including start-stop technology, brake energy regeneration courtesy of an alternator that only engages
during deceleration, careful attention to aerodynamics and low rolling resistance tyres. But its key asset is a lean-burning 163bhp diesel engine that offers an outstanding compromise between power and efficiency.

Official numbers include emissions of 109g/km and 68.9mpg combined, but it's the 320d's 78.5mpg extra-urban fuel economy that really hits home - slightly superior to the Prius's 76.4mpg extra-urban rating. Of course, these figures are generated by the EU's test cycles - actual fuel consumption usually falls short - but, if anything, diesels are closer to delivering on claimed fuel efficiency than hybrids.

The final piece of the puzzle is the question of non-CO2 emissions, says iCAR. Put simply, petrol engines used in current hybrids release far fewer overall pollutants. Despite the use of filters, diesels unleash many more unburned carbon particulates into the atmosphere than petrol cars.

"For Londoners battling stop-start traffic, a petrol-electric hybrid is cleaner and greener," says Laird. "But for extended journeys out of town, you can't beat the long-haul efficiency of a good diesel. One-size-fits-all motoring is history, that's the bottom line."

More at icarmagazine.co.uk

Living is easy with the Renault Twizy

If you don't fancy hybrid or diesel, how about going electric?

Renault's tiny electric car, the Twizy, is a metre wide and two metres long. Pitched somewhere between a scooter with a roof and a Smart, it looks for all the world as if someone has put a Smart on too hot a wash and the doors have dropped off.

Doors are, in fact, optional. You can have beam-like half doors which hinge at the front and offer a certain amount of protection from the elements, or not bother with anything. The three prototypes Renault showed British journalists in Paris were far from the finished article but did give a hint of how much fun the Twizy will be when it appears early next year.

The version coming to Britain has a top speed of 50mph and accelerates like a scalded cat, thanks to the instant power from its 20bhp electric motor mounted at the back. Fears that such a tall and narrow car would topple over evaporated at the first bend, when it just dug in and drifted in a controlled manner at a speed that felt much faster than it was.

The 100kg of batteries are under the driver's seat, keeping the centre of gravity low, and hardened motoring hacks all returned from their test track laps with broad grins.

The controls are conventional: steering wheel, brake, accelerator and a digital read-out giving speed, range etc, although these were not complete on the prototypes. Range will be 60 miles - more than enough for most short journeys - and seating for two is tandem-style.

The simple construction should keep repair costs - and therefore insurance - low. Who knows, with its low top speed, this could even be a car 17-year-olds could afford to insure and still enjoy.

Mike Stone

Create a FREE account to continue reading

eros

Registration is a free and easy way to support our journalism.

Join our community where you can: comment on stories; sign up to newsletters; enter competitions and access content on our app.

Your email address

Must be at least 6 characters, include an upper and lower case character and a number

You must be at least 18 years old to create an account

* Required fields

Already have an account? SIGN IN

By clicking Create Account you confirm that your data has been entered correctly and you have read and agree to our Terms of use , Cookie policy and Privacy policy .

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged in