Brake Energy Regeneration on New BMW 5 Series

BMW has announced details of the revised 5 Series Saloon and Touring range – a mid-life ‘refresh’ programme with new engines and technologies – and the firm claims there is an improvement in economy by up to 25 per cent.

High Precision Fuel Injection is offered for the first time on all six-cylinder petrol-powered 5 Series models. Piezo crystal injectors that deliver a precise amount of fuel mixture, exactly when required, offer a significant increase in performance and economy. This is complemented by a BMW first – Brake Energy Regeneration.

Brake Energy Regeneration appears for the first time on any BMW and forms a key component of BMW’s ‘Efficient Dynamics’ programme. ‘Efficient Dynamics’ focuses on three specific areas – weight, dynamics and consumption – with the intent of developing more power from less fuel in a lower-weight vehicle.

Brake Energy Regeneration takes advantage of energy currently lost through the engine over-run during braking. It uses Intelligent Alternator Control and a high-capacity Absorbent Glass Mat battery. When engine over-run is recognised, the Intelligent Alternator engages and powers up the battery to 100 per cent with what would have been lost energy. It also reduces drag on the engine by only engaging and charging when required. BMW say that Brake Energy Regeneration will combine with other technologies and products during 2007 to provide even greater efficiency benefits. In isolation, it provides an average three per cent reduction in fuel consumption and emissions.

All nine power units in the 5 Series Saloon and Touring ranges are either entirely new to the car, or have been significantly revised over the previous model.

The most economical options are the petrol 523i and the diesel 520d. Some performance figures are shown below, with improvements over the outgoing model in brackets.

The 523i has a straight-six petrol engine with second-generation High Precision Direct Injection, 2,497cc, max output 190hp (+13hp), acceleration 0–62mph 8.2 secs (-0.3 secs), top speed 147mph, average fuel consumption 38.7mpg (-16.6 per cent) ) (automatic transmission 37.7mpg (-24 per cent)).

The 520d has a four-cylinder diesel with common-rail fuel injection and variable vane turbocharger, 1,995cc, max output 163hp, acceleration 0–62mph 8.6 seconds, top speed 139mph, average fuel consumption 47.9mpg (automatic transmission 40.9mpg).

The new BMW 5 Series range starts production in March 2007, with prices ranging from £26,980 OTR (520d SE Saloon) to £49,805 OTR (550i M Sport Touring).