BMW: using less to get more from the engine

BMW's new technology can cut out the power to cut down on emissions, writes Paddy Comyn

We have written extensively here in Motors about the pressure that is being put on car manufacturers to produce more efficient and indeed cleaner cars. The EU has proposed rules requiring carmakers to cut carbon dioxide emissions from new cars to an average of 130 grams per kilometre by 2012.

And as we reported last week, the Department of Finance is said to be rethinking its reforms to the current Vehicle Registration Tax (VRT) system so that they will take full account of a vehicle's emissions, and no longer base charges on engine size.

This proposed 2012 target is a tough call for even the most efficient of small car manufacturers. However, when you are primarily a luxury and sports car manufacturer then the mission seems even closer to the impossible kind. But BMW was one of the most vocal of the distributors at a local level to have VRT-based on CO2 emissions, rather than just engine capacity, and the reasons for this are now becoming even more relevant.

Last week, at their Spring Model Update, where changes to their new model range were unveiled, the highlight was the release of details of the German firm's EfficientDynamics strategy.

Quite simply, this is a drive to achieve lower emissions and improve fuel economy, yet giving even better performance and driving dynamics. The new BMW 1-Series, which now comes available as a three-door, boasts the majority of the new EfficientDynamics technology.

Technologies such as brake energy regeneration, automatic stop-start function and electric power steering are combined with lower resistant tyres and a gearshift change indicator to encourage economical motoring. These innovations are in addition to the use of variable valve technologies and high-precision direct injection engines on some 1-Series models that boost power output, but cut fuel consumption and emissions.

Brake energy regeneration makes its debut on the 1-Series. The system uses an intelligent alternator control (IAC) and an absorbent glass mat battery to recycle previously lost energy, in turn saving fuel.

The IAC reduces drag on the engine by only engaging when required to charge the battery, whereas a traditional alternator is always pulling power from the engine. It also turns potentially lost kinetic energy from braking or descending a hill into a way of charging the battery. This system alone will improve fuel economy by 3 per cent.

The new 1-Series also comes with automatic start-stop function to cut fuel consumption. The system automatically switches the engine off when the vehicle is stationary, and the driver puts the car into neutral. To restart, the driver needs only to engage the clutch again before pulling away again as normal. This is very simple to use and despite what you might think, modern engines are so efficient that it is more efficient to shut them down and start them again rather than leaving them running in traffic.

IT IS PROBABLY BEST not to take this car to your driving test, however, although this system can be manually turned off. Besides this, there is a gearshift indicator that tells you when to change for optimum economy, plus low-rolling resistance tyres, plus the use of electric power steering results in a 90 per cent saving compared to a conventional mechanical hydraulic steering system.

Power assistance is now provided by an electric motor that works when required, such as turning a corner. The air conditioning power supply is now disconnected from the drivetrain when not in use. There are even flaps behind the kidney-shaped front grille which close up to improve the aerodynamics and thus improve fuel economy.

What this equates to in real terms is that, across the range, emissions have been cut by up to 21 per cent and fuel consumption has been improved by up to 24 per cent. The 118d, which is BMW's more economical car, will now achieve a staggering 4.7l/100km (60.1mpg) while recording a very low 123g/km CO2.

All this comes with changes to the five-door 1-Series to improve its looks and aerodynamics. These include a bigger grille, lower front spoiler, restyled headlamps and a restyled bumper at the rear. The new three-door model gives the car a sportier gait, with longer passenger doors, which are frameless.

Buyers can choose between a four or five-seat configuration for the three-door. There are also improved functionality features on all cars, such as MP3 and USB connectivity. The new three-door model starts with the 118i, which gets all the EfficientDynamics technology. Prices start at €33,750 on the road.

The revised five-door model starts with the 116i for €30,450, but for now this volume model does not get the EfficientDynamics technology such as Start-Stop. BMW Ireland tell us that they will have a version of that in time for January 2008.

For us, the model to choose is the über-efficient 118d which is incredibly frugal, yet gutsy enough for most tastes. Prices start at €35,150 for the three-door version and €36,250 for the five-door 118d. Should there be a major change in VRT, this particular model with its 123g/km CO2 could end up being the cheapest in the range, but either way this is still the "1" to buy.BMW doesn't do "facelifts" it seems. Instead they do Life Cycle Impulses (LCI). Perhaps we will see Hollywood actors nipping off for an LCI in future.

Either way, the 5-Series (pictured) has been revised and visually these changes include at the front, headlamps and indicator units that use clear glass technology while the kidney grille sits flush with the bumper. The air duct in the front valance has also been redesigned, while at the side the sill has an additional contour line.

At the rear, the indicators, running and brake lights now use horizontal LED light bars. Inside, there are changes to the door panels and there are now eight programmable 'favourite' buttons on the dashboard, enabling drivers to access their most frequently used features, such as calling home, at the touch of a button. As well as this, the Brake Energy Regeneration appears to reuse braking energy to charge the battery, and the engines are now running more efficiently to save fuel.

There are options available such as Head-Up Display and Night Vision and a Lane Departure Warning System. There is also the option of Active Cruise Control with Stop & Go. This new system will keep the car in front at a fixed distance ahead, even in slow moving stop and go traffic situations, bring the car to a complete stop. If the period of standstill is less than three seconds, the car will resume its programmed speed.The new 5-Series range is priced from €53,750 for the 520d SE Saloon.