The clean Mercedes-Benz BLUETEC commercial vehicles are trendsetters for the car sector, as the highly innovative system for reducing nitrogen oxides and other emissions also lends itself to application in passenger cars: BLUETEC reduces nitrogen oxides to such an extent that the toughest emission limits worldwide can be met. An advanced concept car with a forward-looking hybrid drive, in the shape of the S 320 BLUETEC HYBRID, was already shown by Mercedes-Benz at the Frankfurt International Motor Show in 2005. With an electric motor integrated in the powertrain, the concept car is a “mild hybrid”, with significantly reduced fuel consumption especially in inner-city stop-and-go traffic. The diesel engine switches itself off whenever it is not required. All the modifications and features combined reduce the fuel consumption of the BLUETEC HYBRID by some 20 percent versus the comparable predecessor model. The combined output of this S-Class car is 243 hp (179 kW); the combined torque is as high as 575 Newton meters. The car accelerates from standstill to 100 km/h in 7.2 seconds, and its top sped is electronically limited to 250 km/h (155 mph). Fuel consumption (New European Driving Cycle) is as low as 7.7 liters per 100 kilometers (30.5 mpg).

In early 2006 the Stuttgart people then presented BLUETEC for passenger cars as a ready-for-production package consisting of several components. The extensive optimization of the engines and the combustion processes taking place inside them constitutes the basis of this package. With solutions like multi-hole injection nozzles, the use of the latest generation of CDI technology and other measures, the raw emissions are cut to an extremely low level. This is where the emission control system with an oxidation-type catalytic converter (for hydrocarbons and carbon monoxide) and a particulate trap comes in. The final stage is nitrogen oxide reduction by the BLUETEC component proper.
It’s the world’s cleanest diesel: in October 2006 the E 320 BLUETEC hits the US market as the first production BLUETEC car; the market launch of BLUETEC cars in Europe is scheduled for 2008. The E 320 BLUETEC is an innovative model which is based on the sophisticated 320 CDI V6 and relies on the BLUETEC technology developed by Mercedes-Benz. BLUETEC is the designation for a highly efficient method of minimizing nitrogen oxide emissions already used in commercial vehicles. In contrast to commercial vehicles, the E 320 CDI BLUETEC does not make use of AdBlue injection but reduces nitrogen oxides with a system based on an improved storage-type catalytic converter.

The question may occur why the E 320 BLUETEC makes its debut in the USA. One reason, of course, is the growing demand for economical and at the same time clean cars in that country, caused by rising fuel prices. But there’s yet another reason for this specific timing: “The introduction of clean diesel fuel in the USA is something we have been fighting for alongside others for a long time, and an opportunity we wish to use from Day One,” said Thomas Weber, head of Corporate Research at DaimlerChrysler and of Development within the Mercedes Car Group, when the car was introduced in Las Vegas, Nevada. Modern diesel-engined cars which, in West Europe, account for more than half of new registrations annually, were unable to develop their full potential in the USA due to the excessively high sulfur content in the fuel until now. This changes at the end of 2006 thanks to the nation-wide introduction of clean diesel fuel with a sulfur content of just 15 ppm. The so-called Ultra Low Sulfur Diesel (ULSD) will be available at up to 76,000 gas stations in the USA in a first step and thereby permit the use of BLUETEC. With this innovative diesel technology, Mercedes-Benz is also able to remain below the strictest globally applicable limits where nitrogen oxide emissions are concerned. Hence, all the preconditions for the breakthrough of modern diesel technology in the USA are fulfilled.

The diesel principle has come a long way from Rudolf Diesel’s invention to the modular BLUETEC system. Time and again DaimlerChrysler contributed decisive innovations to develop the diesel drive to its present level. Thus, 70 years since its premiere in the Mercedes-Benz 260 D, the compression-ignition engine presents itself today as a high-performing and economical high-tech drive with the potential for meeting even the toughest international emission limits in the future.

Mercedes-Benz demonstrated the direction in which developments in the passenger car sector are going with the E 320 BLUETEC and with concept vehicles in 2006, first and foremost the Vision GL 320 BLUETEC, the Vision CLS 320 BLUETEC and the Jeep® Grand Cherokee BLUETEC concept car. GL and Jeep® have an SCR catalytic converter with AdBlue injection; the CLS, like the E-Class, features an improved nitrogen-oxide storage-type catalytic converter. In addition, as early as 2005, at the International Motor Show in Frankfurt/Main, the S 320 BLUETEC based on the new S-Class was put on display.

BLUETEC’s tremendous potential in the SUV is impressively illustrated by the GL-Class study. The car is fitted with a V6 diesel engine which yields an output of 155 kW (211 hp) and torque of 540 Newton meters. Thanks to BLUETEC the concept car combines convincing performance with great fuel economy and the lowest emissions: the expected consumption of 9.4 liters of diesel fuel per 100 kilometers (25 mpg) will be 20 to 40 percent less than that of comparable gasoline-engined SUVs, and the car will comply even with the harshest emission laws.

At the 2005 International Motor Show in Frankfurt/Main, Mercedes-Benz presents the S-Class S 320 BLUETEC Hybrid as a luxury-class vehicle in which the low-emission BLUETEC diesel with SCR technology provides the basis for an ultramodern hybrid drive. The electric motor of the hybrid vehicle is integrated into the drivetrain.

In addition, in Paris DaimlerChrysler displays a concept car – the smart fortwo cdi hybrid – in which a diesel drive and electric motor work together. The consumption of the smart fortwo cdi hybrid is expected to be about 2.9 liters of diesel per 100 kilometers (81 mpg), obtained with a sprightly driving style.

SPIEGEL: Can an EU commissioner really drive a Japanese car?

Dimas: Of course. This hybrid is at the top of the German Automobile Club's list of the most environmentally friendly cars.

SPIEGEL: But the VW Polo BlueMotion is also on that list.

Dimas: The Polo is an excellent car, but I need a vehicle for long journeys which, like the Prius, is also big enough to work in. But I do wonder why there isn't a German, Italian or French hybrid that I could drive.

Now, the Toyota Prius hybrid is well known for its silence (in all-electric mode) or near-silence (with the petrol engine in operation), but if that's led you to equate clean running with silent running then this Polo will be a surprise. It is, in fact, one of the noisiest diesel engines around. VW has clearly saved some weight by skimping on the soundproofing. It's most pronounced at low speed but the diesel clatter remains at higher speeds.

It's also very slow. The official performance figures show a 0-62mph time of 12.8 seconds and a top speed of 109mph, but - as with all performance figures - they would be achieved with your foot to the floor and the engine at its least economical. In normal driving, with the driver exercising restraint, the BlueMotion just crawls and clatters along, with the high gearing discouraging anything resembling zipping about.

a day spent driving the BlueMotion on a mix of fast motorway, slow town and reasonably swift B-roads I managed just 438.7 miles from full before my nerve gave out and I had to refuel. I'd used 42 litres of diesel, giving me a fuel consumption figure of 47.5mpg: not bad, but some 24.5mpg shy of the official figure.