2010 Mercedes-Benz S400 Hybrid Sedan

Mercedes-Benz will introduce its first hybrid car in the US market this September in the form of a face-lifted S-Class (the BIG Mercedes) sedan, the S400 Hybrid. It's also the first time that the current generation S-Class (internal designation W221 for geeks like me) will have a V6 engine rather than a V8 or V12.

In the US, we expect the Big Benz to have a big engine. However, in the rest of the world, the S-Class volume leader has a V6 turbo-diesel engine.

In the UK, for example, the S320 CDI accounted for more than 80% of sales. Why bring a pricey hybrid to a market where the top-selling, much cheaper, turbo-diesel model gets similar fuel economy?

There will be endless articles and tests of the new S400; however, the biggest question is will it sell, particularly in LA, the native environment for the big Merc? The economic downturn has hit everyone, even the rich entertainment suits and above-the-line talent here. Yet an S-Class is such a ubiquitous car on the Westside; I don't see a problem with sales here.



I use the word “sales” loosely because most of these cars are leased. I remember when the new S-Class was unleashed in the LA market in January 2007.

Within a few months, just about every “old” S-Class had been traded for a new one. They couldn't sell them fast enough at Beverly Hills Mercedes or W.I. Simonson in Santa Monica.

Most of these cars are leased for three or four years, so the first leases of the new W221 S-Class will be terminating early in 2010.



The base Merc S550 starts at $90,000. Mercedes-Benz USA hasn't announced pricing yet for the S400 Hybrid; however, speculation is that it will carry a $15 - $20,000 premium over the “entry level” S550.

A well-equipped S-Class sedan usually has $15,000 in options, so the S400 may carry a sticker price of $120,000. If you look at a 3 year lease, the additional payment is only an extra $250 - $400 a month. In LA, that's chump change, particularly when it comes to bragging rights and “green creds” at a cocktail party or in the studio parking lot.



Countless people have ponied up an extra $5k for the hybrid Lexus RX and it doesn't even get much better fuel economy than the base RX V6. However, the Lexus hybrid more comparable in size and form to the Mercedes S400 is the 2009 Lexus LS600h with a base sticker price of $106,910 – a whopping $32,300 premium over the LS460 (long wheel base). At those lofty premiums, it's all about show, not about saving the planet.

Mercedes-Benz S-Class customers are a loyal breed and they have been conditioned to pay top dollar for the “pinnacle” of German engineering. (BMW might dispute that claim with its new 7-Series.) The 2009 S65 AMG with the twin-turbo Maybach V12 engine has a base sticker of $198,950, so who is going to blink over a measly $120k for a hybrid?



Mercedes is playing down its expectations for the sales volume of the S400. It's better to set the bar low and then brag if you manage to do better.

Let's look at the basics for the new S400. It's a “series” hybrid because the electric motor is sandwiched (in series) between the engine and Mercedes' excellent 7-speed automatic transmission. The corporate 3.5 liter V6 engine has 275 hp and 255 lb-ft torque. The electric motor adds 20 hp and 118 lb-ft torque for combined totals of 295 hp and 283 lb-ft torque at 2400 rpm.

In any normal car, these figures are more than adequate to fly around town; however, the S400 Hybrid tips the scales at a hefty 4,575 lbs. Mercedes claims that the hybrid drivetrain will sling the S400 to 60 mph in 7.1 seconds and with the ultra-slick hybrid-tuned 7-seed automatic transmission, you'll barely feel the shifts. Top speed is limited to 130 mph. Oh, the sacrifices one makes to be socially conscious.



Mercedes claims that the S400 Hybrid will be rated at 23 mpg city 34 mpg highway with combined fuel consumption of 29 mpg. That beats the pants off the Lexus LS600h which is rated at 20 city/22 highway. The Lexus, however, will beat the treads off the Mercedes' low-resistance tires with a zero to 60 time of only 5.5 seconds. Still, the S400 Hybrid will be, by far, the most fuel efficient full-sized luxury sedan sold in the US.

The big innovation in the S440 Hybrid is its lithium-ion battery pack. Mercedes, which just bought 10% of electric car maker Tesla Motors, is using lithium-ion battery technology similar to that found in Tesla's Roadster. The 32 cell, 120 volt, 0.9 amp-hour battery is about the size of a (big) shoe box and it's fitted under the hood, in the front right corner of the engine compartment. Accordingly, there is no compromise in the trunk capacity or back seat room of the big Mercedes.

As with other hybrids, the kinetic energy generated by the electric motor during braking is used to juice up the lithium-ion battery pack. The big problem with any lithium-ion battery is cooling it.

Just think of all the laptop computers and other electronic devices that have had a little fire problem from overheating. The battery itself is assembled by German supplier Continental with cells manufactured by French supplier SAFT at a new, state-of-the-art factory in Narsac, France. [SAFT also operates a joint venture battery operation in the US with US supplier Johnson Controls.] Mercedes cools the battery by running the AC system's refrigerant circulated with its own electric pump (which is necessary when the car is off).




For 2010, all S-Class models get a mild face lift and some additional gee-whiz electronic gadgets: Adaptive Highbeam Assist, Lane Keeping Assist and PRE-SAFE brake systems are linked to a proximity-regulating radar which intervenes autonomously before an impending rear-end collision and acts like an “invisible crumple zone.”

Other electronic innovations include Attention Assist to wake drowsing drivers and Active Body Control with Automatic Crosswind Stabilization. I'm sure this is a must-have option for driving to windy Palm Springs.

The S400 hybrid is considered a “mild hybrid” because it can't operate in electric-only mode. But it is only the first in a line of hybrids Mercedes plans on bringing to the US market. In 2010, we get a “full hybrid” ML SUV to be built in Alabama that uses the two-mode hybrid system jointly developed with GM, Chrysler and BMW.

A full hybrid S-Class should follow the S400 in a few years.
Gallery: 2010 Mercedes-Benz S400 Hybrid Sedan