After years of claiming that blue is the new green (in reference to its BlueTec diesel developments), Mercedes-Benz has taken a side step and introduced a hybrid to the market, the S 400 BlueHybrid. The modified S-Class sedan benefits from the addition of Mercedes' first hybrid drivetrain and the world's first implementation of a lithium ion battery in a production vehicle.
The battery, which makes this whole deal possible, is remarkable in that it's surprisingly compact thanks to lithium ion tech. The entire assembly is only slightly larger than a standard 12-volt car battery. The small size allows the battery to be located in the engine bay, where it replaces the conventional starter battery. This underhood placement, as opposed to a huge NiMH battery under the floor or in the center tunnel, means the S 400 BlueHybrid doesn't sacrifice interior or trunk space in the name of economy.
The modified V6 engine that powers the BlueHybrid has been "hybrid-ized" with the addition of a 20 horsepower disc shaped electric motor that is sandwiched between the gasoline powerplant and the 7G-Tronic automatic transmission, which produces 188 foot-pounds of torque. The electric motor boosts the output of the gasoline engine, but most of the efficiency gains are attributed to the way the electric motor works with the engine start-stop function. With the electric motor working as a starter, the engine can be shut off at speeds below 9 mph and instantly spun back up when it's time to go back onto gasoline power. Working together, the gas and electric powerplants generate 299 horsepower and 285 foot-pounds of torque and a pretty good combined fuel economy of 29 mpg. The S 400 BlueHybrid sits somewhere between the Lexus LS 600h L and the Toyota Prius on the gas-electric performance scale.
Inside the cabin, the S 400 BlueHybrid gets the requisite drivetrain monitoring displays that most hybrids seem to come with these days. Upon closer inspection, we see that the entire speedometer has been replaced by an LCD, while the rest of the gauges (tachometer, fuel, temp, and so on.) remain traditional.
Looking at the horsepower, torque, and fuel economy numbers again, it's fairly obvious that the primary goal of the hybrid system is to boost the performance and economy as opposed to push hybrid technology to new levels of efficiency. It's fairly obvious that Mercedes hasn't stopped believing in the merits of the diesel powered engine, because they've essentially recreated diesel performance with the hybrid drivetrain.