BMW's most efficient 3 Series ever

This is the greenest most fuel-efficient BMW 3 Series model ever made - the new 320d Efficient Dynamics saloon.

Its CO2 emissions are just 109g/km and it can achieve an impressive average of 68.9mpg.

Mechanical changes
From an engine stop-start system to brake energy regeneration, the new model gets the full range of BMW's Efficient Dynamics technology.

Other changes to improve fuel consumption and cut CO2 emissions on the new 320d Efficient Dynamics include:

• Longer gearing;
• Lowered suspension;
• Aerodynamic alloy wheels;
• Michelin Energy Saver tyres;
• Changes to improve drivetrain smoothness.

As with the standard 320d, the Efficient Dynamics model has a 2.0-litre diesel engine, but with 161- rather than 175bhp. Maximum torque is up from 258lb ft to 266bhp.

The changes make the Efficient Dynamics model much cleaner and economical than the standard 320d, which averages 58.9mpg and emits 128g/km. It's even more efficient than the recently launched 316d, which emits 118g/km and averages 62.8mpg.

The 320d Efficient Dynamics will cost just 35 a year in road tax and falls into the lowest possible category for company car tax, which is 13%.

Lots of standard kit
The 320d Efficient Dynamics will have the same standard equipment as the 320d SE model, but with 16- rather than 17-inch alloy wheels. Other kit includes dual-zone climate control, reversing sensors and a multi-function leather steering wheel.

The price will be equivalent to the 320d SE's, too, which currently costs 26,680.

The new 320d Efficient Dynamics goes on sale in January.