NOTE: Pricing based on data collected March 2011. Costs of hybridization and forced features are UCS estimates based on information available on manufacturer websites. The negative cost of hybridization is due to savings from the downsized engine in the S400 Hybrid.
See full Hybrid Scorecard methodology
Mercedes-Benz introduced the S400 Hybrid, its first hybrid, in model year 2010. With a 3.5-liter, six-cylinder engine, the 2011 S400 Hybrid is a five-seat luxury sedan and gets a combined EPA estimated fuel economy of 21 miles per gallon (mpg). With the S400 Hybrid, Mercedes-Benz has combined hybrid technology with a downsized gasoline engine to create a hybrid model that actually costs less than its conventional counterpart—a first among hybrid vehicles when it debuted in model year 2010 . Unfortunately, the hybrid drivetrain does not capitalize fully upon the engine downsizing, delivering only modest environmental gains. The S400 Hybrid is a mild hybrid, offering idle stop/start, power assist, and regenerative braking; it cannot run on electric power alone (a feature that makes a vehicle a “full” hybrid). It is also the first production hybrid using lithium-ion batteries. Lithium-ion batteries offer greater energy storage per pound and are expected to increase electric-only range in future full hybrids and plug-in hybrids.
Environmental Improvment Score
The S400 Hybrid gains a 14 percent reduction in global warming emissions compared with the conventional S550 . The low smog-forming emissions of the S400 Hybrid results in an EPA air pollution score of 9 out of 10. These combine for an overall Environmental Improvement Score of 5.3.
One might expect a greater reduction in global warming emissions given that Mercedes-Benz downsized to a V6 engine, resulting in a vehicle that has about 30 percent less horsepower than the V8 engine in the S550. Yet, the Infiniti M Hybrid achieves a 28 percent reduction in global warming emissions without engine downsizing.
It’s interesting to compare the S400 Hybrid with the non-hybrid E350. While the S400 is in the higher-end S-Class, both vehicles have the same-sized V6 engine and the E350 only gets 1 mpg less than the S400. Yet, the S400 Hybrid weighs 649 pounds more than the E350 and has a slightly slower 0–60 acceleration time (7.2 seconds versus 6.5 seconds). Based on these factors, it looks like downsizing the engine gives the S400 most of its fuel economy gain, while the hybrid system mainly offsets the remaining fuel economy difference caused by the extra weight.
Mercedes should be applauded for downsizing to the more efficient V6 engine, but should focus on getting even better fuel economy in the future by adding a full hybrid system or beefing up the mild hybrid system.
Scorecard Environmental Improvement Score methodology
Without a price premium for the hybrid system, the S400 Hybrid easily rates “Superior” on the Hybrid Value scale. Indeed, given that the S400 Hybrid comes in at $2,000 less than the S550, one can plainly see the cost savings that can be realized by combining a hybrid drivetrain with a smaller, more efficient gasoline engine. That said, however, Mercedes-Benz offers an interesting conventional alternative in its “E Class” midsize sedans. As noted above, the non-hybrid E350 gets 20 mpg fuel economy and faster acceleration than the S400 Hybrid, yet at $49,400 costs over $40,000 less.
Scorecard Hybrid Value methodology
By design, Mercedes-Benz offers premium features even on its base models. On the whole, the S400 Hybrid’s standard features are almost identical to those in the S550. For this reason, the S400 Hybrid earned a Forced Features rating of “None.” This is in stark contrast to the Lexus LS 600h L, which piles on almost $11,000 worth of forced features.
Scorecard Forced Features methodology
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