Mercedes-Benz developed this new 4.6-liter V-8 with direct injection and twin turbos.
After Mercedes-Benz launched its 5.5-liter V-8 in the 2005 S550, that engine found its way into almost every other Mercedes-Benz model. It appeared in the CL, CLS, E, ML, GL, G, and SL class cars. Now, Mercedes-Benz has developed a new V-8 using direct injection and turbochargers, which will first appear in the upcoming 2011 CLS550.
If Mercedes-Benz stayed true to its model naming convention, this new CLS would be called the CLS460 Kompressor, or possibly Doppel-Kompressor. The new V-8 is smaller than its predecessor, displacing 4.6-liters, yet makes more power. The new engine achieves 429 horsepower and 516 pound-feet of torque, a big boost compared with the 5.5-liter engine's 382 horsepower and 391 pound-feet of torque. At the same time, Mercedes-Benz says the new engine will get 20 percent better fuel economy.
Direct injection is one technology helping the engine meet these specifications. Fuel injectors are mounted in the cylinder, spraying the gasoline mixture directly into the chamber, resulting in a more efficient burn than port injection provides. Twin turbochargers also account for a portion of this power boost. Mercedes-Benz says it tuned the turbos for low-speed torque, with 443 pound-feet coming on at 1,600rpm, making turbo lag unlikely.
The engine is also optimized for start/stop operation, allowing it to shut down when the car is stopped at a red light or in traffic. This feature has become popular in Europe, but in the U.S. has been used only in hybrids to date.
The 2011 CLS with this new V-8 goes on sale this fall.
source: review.cnet
