2010 Mercedes-Benz S400 Hybrid: Is This Luxury Fuel Saver for You?

For the 2010 model year, Mercedes provides its first hybrid with an S-class
offering. It is an indication that the auto maker is moving off of an all diesel
approach to acknowledging that the hybrid powertain is a worthwhile
intermediate step on the way to an all-electric Mercedes.

The Mercedes S400 Hybrid is the world's first electric vehicle to use
lithium-ion batteries. Hybrid vehicles have been around for a number of
years now, however, they are rare in the luxury class as only Lexus has
provided an offering for the past two years.

The Mercedes approach to building a hybrid is quite straight forward in that
it uses a compact ring-shaped electric motor located between the engine and
the car's automatic transmission. Like the current hybrids on the market, the
S400 Hybrid has regenerative braking and it shuts down the engine at stoplights
to save additional fuel.

Mercedes is choosing to introduce the hybrid as a more environmentally
conscious way of driving in luxury. The S400 Hybrid, which will be
available in September of 09 as a 2010 model, is expected to cost about
the same as a $90,225 V8 powered S550.

The S400 Hybrid has a 3.5-liter V-6 engine providing 275 hp. This is the
same horsepower as the base V8 engine provided in 2006. The hybrid's
V6 engine is similar to the one used in other Mercedes cars and crossovers,
however, it has different pistons and cylinder heads.

Additionally, the engine runs on the Atkinson cycle, which is a common
among hybrids. The Atkinson cycle uses late closing intake valves
to increase the power stroke for better efficiency. This approach causes
the engine to forgo some torque especially at lower rpms. The electric
motor, however, provides extra low-end torque. Thus, the total power
of the S400 Hybrid is stated at 295 hp and 284 lb. ft. of torque. This is
above the 268 hp and 258 lb. ft. rating of a C-class equipped V6 engine.

The S400 Hybrid will reach 60 mph in about 7 second. This does not
match the S550's time of 5.4 seconds, however, the fuel savings for the
hybrid is substantial. Mercedes expects the S400 Hybrid to achieve
23 mpg in the city and 33 mpg on the highway. This represents a fuel
savings of about 50 percent over the V8 engine.

One other important aspect of the S400 Hybrid is its cargo volume in
the trunk. At present, hybrids have reduced trunk capacity because their
large nickel-hydride batteries take up space not to mention the
substantial weight added to the car.

The Mercedes S400 Hybrid uses smaller more energy dense lithium-ion
batteries. The batteries consist of thirty-five cylindrical cells supplied
by a French firm named Saft. All the batteries are located in the Mercedes'
engine compartment. This leaves the S400 Hybrid's truck intact and allows
16.3 cubic feet of cargo carrying space.

In time, Mercedes plans to offer the hybrid option on more of its cars
and SUVs. This is a good way of insulating its customers from future
oil price increases.

Be sure to test-drive an S400 Hybrid at your local Mercedes dealership. You
will be glad you did!

Kyle Busch is the author of "Drive the Best for the Price..." He
welcomes your comments or car questions at his auto web site:
www.DriveTheBestBook.com.