This autumn Britain’s favourite sports saloon, the BMW 3-series could receive green engine technology that can improve fuel economy and carbon dioxide emissions by over 15 per cent.

A suite of engine add-ons and equipment upgrades known as ‘mild hybrids’ will be fitted on all the four-cylinder diesel and petrol engines sold by BMW.

These technologies further improve the internal combustion engine without the drawbacks suffered by other green technologies.

With 17 per cent more power (143bhp) than the old 1.8d, combined fuel economy improved to an astonishing 60mpg from 50mpg, while CO2 drops to a near-hybrid level of 123g/km, the ‘Efficient Dynamics’ technologies have had stunning effects on BMW’s 1.8-litre diesel, just launched in the new 118d.

An integrated starter motor/alternator, computerised alternator control, auto stop/start and electronic power steering -these are four features part of ‘Efficient Dynamics’ technologies.

The technology demonstrate a highly significant features but they are all invisible to the driver, the most noticeable beeing the stop/start, which cuts out/in at 2mph when the clutch is depressed in neutral.