In October 2004, Mercedes-Benz unveiled the four-door CLS-Class as a new kind of vehicle concept that for the first time combined the dynamism and features of a coupé with the comfort and functionality of a saloon. In mid-2006, Mercedes-Benz will be further enhancing this series’ exclusive range of equipment and cutting-edge technology. In doing so, it will particularly set new standards with regard to safety and engine technology.
The world’s first direct petrol injection system with spray-guided combustion points the way ahead for passenger car petrol engines, and will be available in the new CLS 350 CGI from the third quarter of 2006. The engine’s innovative injection procedure makes for much better fuel and thermodynamic efficiency than the wall-guided combustion process previously employed with direct injection. With a fuel consumption of 9.1–9.3 litres per 100 kilometres(62.13 miles) in the European driving cycle, the six-cylinder Coupé has a range of approximately 70 kilometres(43.49 miles) on one tankful (80 litres).
The main advantage of the CGI engine (CGI = Stratified-Charged Gasoline Injection) lies in the stratified operating mode from which it takes its name. In this mode the engine is run with high excess air and thus excellent fuel efficiency. Now, thanks to multiple injection, it is for the first time possible to extend this lean-burn operating mode to higher rpm and load ranges too. During each power stroke, a series of injections takes place, spaced just fractions of a second apart. This has the effect of significantly improving mixture formation, combustion and fuel consumption.
Among the most important components of this innovative direct petrol injection system are the fast-acting piezoelectric injectors. They have nozzles which open outwards to create an annular gap just a few microns wide. This gap shapes the fuel jet and produces a uniform, hollow-cone-shaped spray pattern. The microsecond response times of the piezoelectric injectors provide the basis for delivering multiple injections per power stroke, and thus for lean-burn operation. By allowing flexible and efficient control of the combustion process they play a key part in ensuring the engine’s outstanding fuel efficiency.
| Effortless performance twinned... |