State-of-the-art diesel power for all vehicle body types
With its fleet of silver diesel cars in Geneva, Mercedes Benz is showing the direction in which developments will be headed in the future. This claim is highlighted by the uniform paint job for the show cars, which also points the way to the future. The paint covers the body panels like a metallic skin, emphasises the design lines more strongly than any previous paint job and makes them more lively by means of targeted light reflections. The paint’s remarkable sparkle and brilliance is the result of a newly developed process that was used for the first time by Mercedes Benz. While the pigments in a conventional metallic paint measure between 100 and 300 nanometres in size, those in the new ALU-BEAM paint are even smaller (30 to 50 nanometres). In addition, the pigments are specially worked so that they are more uniformly spread within the paint’s surface. As a result, light is reflected with even greater brilliance and the paint’s sheen is substantially enhanced.
The seven diesel show cars also demonstrate the current engines’ extremely wide range of possible applications. In line with their high technical demands, the Mercedes engineers have made the engines so exceedingly clean and powerful, and at the same time smooth-running, that they can be easily used with all vehicle body types.
The direction in which the engineers at Mercedes Benz are taking compression ignition engines is being shown in Geneva by the two diesel-powered roadsters that boast record performance figures. A new V8 engine generates 315 hp in the Vision SL 400 CDI and provides the eight-cylinder’s crankshaft with an outstanding torque of 730 Nm. The SLK 320 CDI tri-turbo, meanwhile, can generate an impressive 286 hp and 630 Nm of torque from three litres of displacement (94.3 hp and 211 Nm per litre of displacement).
Three turbochargers in the SLK-Class
The SLK 320 CDI tri-turbo is based on the new V6 diesel engine, which achieves new levels of performance thanks to a two-stage supercharging system. It consists of three turbochargers, of which two are located on the outside next to the cylinder banks while the larger third turbocharger is situated between the V of the cylinders. At low engine speeds and loads, air flows through all three turbochargers (i.e., large and small), with the small turbochargers doing most of the work. When engine speed increases and the flow is continuous, the large turbocharger takes over supplying the greatest share of the charge pressure and the smaller turbochargers are turned off by means of a bypass system. At high engine speeds and loads, only the large turbocharger is running. Performance is further heightened as a result of an enlarged intercooler and larger pipe diameters for the charge air and the exhaust.
Sporting a modified tachometer with a red zone extending from 4,500 to 5,000 rpm and the self-confident appearance of the SLK 55 AMG, the vehicle is a proud member of the Mercedes Benz diesel family. The new engine gives the roadster an impressive boost and allows it to perform prodigious feats: it takes the car but 5.3 seconds to accelerate from 0 to 62.5 mph, and it can travel a distance of 1,000 metres in just 24.4 seconds from a standing start. The top speed is meanwhile electronically limited to 155 mph. With this kind of performance, the SLK 320 CDI tri-turbo has a unique standing even among thoroughbred sports cars. And fuel economy is just as impressive, since, despite the incredible driving performance, the diesel roadster achieves 37.7 mpg (NEDC overall consumption).