2010 Mercedes-Benz ML450 Hybrid

2010 Mercedes-Benz ML450 Hybrid

Mercedes-Benz is just launching itself into the hybrid game, with two separate models for the coming year: the 2010 Mercedes-Benz ML450 Hybrid and the 2010 Mercedes-Benz S400 BlueHybrid.

But even as they ready these cars for dealers and buyers, the company is apparently rethinking its hybrid strategy. From a test drive of the new 2010 E-Class cars outside Las Vegas, our editor Marty Padgett reports that Mercedes may be moving away from the Two-Mode Hybrid system it jointly developed with GM, its former (and newly bankrupt) partner Chrysler, and BMW.

Instead, the company's own mild-hybrid system will spread from the 2010 S400 Hybrid into the new E-Class in a "couple of years." Mercedes is moving toward mild hybrids as a solution, a la the Honda approach, according to Bernhard Glaser, general manager of product management for Mercedes-Benz USA.

In other words, Mercedes-Benz sees a better payback for owners from a minimal hybrid system that only offers launch assist for the engine, rather than full electric running like the Two-Mode.

In the S400 BlueHybrid, that means a thin 15-kilowatt electric motor sandwiched between a 275-horsepower V-6 engine and the company's seven-speed automatic transmission. The motor adds torque to the engine under heavy loads, restarts the engine when it stops at rest, and helps the car move away from rest in the second or so before the engine switches on.

The result is almost 30 miles per gallon (or 7.9 litres/100 km on the European test cycle), quite respectable for a full-size sedan weighing more than 2 tons.

Another advantage: the S400 system requires no body re-engineering, unlike the larger 1.8-kilowatt-hour nickel-metal-hydride pack used in the ML450. Instead, the lithium pack replaces the car's standard 12-volt battery, with a loop of the air conditioning system routed through it to keep the cells cool.

While Glaser didn't explicitly say that the company is moving away from the Two-Mode system, neither did he show much enthusiasm about its future. He told Padgett the lithium-ion cells used in the mild hybrid system are definitely the future, although Mercedes is not unhappy with its learning experience from the joint development of the Two-Mode system.

Earlier this year, Daimler cut back its staff at the joint hybrid development center in Troy, Michigan. Many of those engineers were quickly snapped up by engineering consultancy firms to work on hybrid programs for other companies.

The company still hasn't released pricing for either of its 2010 hybrids. While Mercedes is proud to claim the world's first production hybrid with lithium cells, Mercedes-Benz battery engineer Christian Mordieck said, "the cost is much higher than we would like."

Some analysts have estimated that the S400 BlueHybrid could cost as much as $14,000 more than the S-Class entry price of $88,000.