What Makes Eco Friendly Cars Green/Blue
Tuesday, 20. September 2011
Image via Wikipedia
Car manufacturers love to confuse us poor customers. Just as we had firmly fixed in our minds the colour green as being representative of anything that was environmentally friendly, not only in the UK but around the world, they decided that blue would be the new green (was this a careful ploy on the part of the Conservative party I ask myself). That’s right, we started to see blue this and blue that as being a sign that cars were environmentally friendly and fuel efficient.
Blue Motion is one used by VW and Blue Efficiency used by Mercedes, then we had Eco prefixes but what does it all mean and with one of the most common features of the new breed of ‘Eco’ cars being stop/start technology what’s it all about and does it work?
Well the start point when making a car green (or is that blue) is the engine, all manufacturers are working hard to make their petrol and diesel engines more efficient whilst kicking out fewer CO2’s.
Then there is the re-generation of electricity during cruising and breaking but the most confusing is stop/start. First of all for those that are fearful of the system you can, in most cases, simply switch it off or override it so if you are offered a car with it but don’t like the idea of the engine cutting out on purpose at traffic lights still take it as you can avoid it (check with the supplier first).
So when you stop at traffic lights or in a queue the engine switches itself off and when you touch the accelerator to move away the engine re-starts. If you drive an auto the engine re-starts when you take your foot off the brake. It really is simple and shouldn’t worry you.
The car has a strengthened starter motor to take the extra strain but does it really work? Auto Express carried out experiments on cars with the stop start switched off then switched on with some surprising results. Best performer was the Audi A6 3.0TFSi Quattro (petrol) it went from 24.2mpg to 28.3mpg.
The fuel consumption is still abysmal but it worked with an economy boost of 16.9%. The Smart Car went from 55.9mpg to 63.2mpg an improvement of 13.1%. However, the biggest surprise of all was the VW Golf 1.6 TDi BlueMotion that only had a 0.6% economy boost but it went from 63.2mpg to 63.6mpg.
The reason given was that the engine was now so efficient that the other small changes would always simply make a negligible improvement. So there you have it, how stop/start works and how it doesn’t always improve your fuel consumption dramatically unless you have a big, fuel burning, engine in the first place.
Have you used stop/start? How did you find it, was it of use? By Graham Hill
