Mercedes Unwraps New ML 540 Hybrid SUV

The General Motors, DaimlerChrysler, and BMW joint venture to develop a two-mode hybrid system is bearing fruit on unexpected platforms. At the recent Frankfurt Auto Show, Mercedes pulled the wraps off a 2009 M-Class SUV, the ML 450, with a gasoline-electric two-mode hybrid system.

Clearly, Mercedes is planning to go head-to-head with the Lexus RX 400h luxury hybrid SUV. M-Class SUVs offer two rows of seats that accommodate five adults with the luxurious appointments expected of Mercedes vehicles. Built at the automaker's Alabama assembly plant, the ML 450 Hybrid will be a 2009 model, though an introduction date has yet to be determined.

Mercedes is balancing economy with performance, here. Judging from its powertrain specifications, the ML 450 Hybrid should fit nicely in the Mercedes line-up between the ML 350 and the snarling ML 550. The Hybrid mates M-B's 279 horsepower 3.5-liter V-6 with two electric motors for a combined output of 340 horsepower and 354 lbs-ft of torque.

There's plenty of energy on hand to supply the ML 450 Hybrid's electric motors courtesy of a 288 volt battery pack. The two compact electric motors develop a total power output of 163 horsepower and offer space and packaging advantages compared to other designs. The motors are integrated into the two-mode hybrid transmission. This transmission is quite unique, with four fixed gears offering the benefits of a multi-speed automatic with the smooth delivery of a continuously variable transmission.

The ML 450's V-8 level performance will not sacrifice fuel economy or low emissions. Mercedes claims the Hybrid will consume just 7.7 litres per 100 kilometres, which works out to about 30 miles per gallon. That's considerably better fuel economy than the ML 320 CDI clean diesel variant of this platform. CO2 emissions are equivalent to 185 grams per km. The two-mode system is controlled by an intelligent energy management system. Like other full hybrid designs, the ML 450 will be able to operate solely on electric power, recover electrical energy through regenerative braking, and offer a fuel-saving start-stop function for the 3.5L V-6 internal combustion engine.