Is the Mercedes S400 Hybrid $17K better than the S350 CDI?
Mercedes-Benz S400 Hybrid - Click above for high-res image gallery
With the Mercedes-Benz S400 Hybrid about to hit the market, the very important question of value arises. Until now, for most automakers, there has not been an opportunity to compare basically the same vehicle with hybrid and diesel powertrains. We had hoped to do that next year with the diesel for GM's full-size light duty pickups, but we know how that story ended.
Mercedes is, of course, the original builder of diesel cars and all of its models come so equipped in Europe. While the S400 Hybrid has a clear efficiency advantage over the standard gas engined S350, going from 24 to 30 mpg on the EU combined cycle, the diesel-powered S350 CDI clocks in at an even better 31 mpg. The big difference is the price. In Europe, the S400 Hybrid commands a hefty $17,100 premium over the diesel. There are likely equipment differences between the two, but that's still a pretty absurd premium. It will be even more interesting to see how the prices of the diesel and two-mode hybrid versions of the ML compare when the hybrid goes on sale late this year in the U.S.
Gallery: Mercedes-Benz S400 BlueHybrid
[Source: Automobile]
Reader Comments (Page 1 of 1)
matt 12:51PM (6/17/2009)
sounds like a no brainer for the diesel to me... 17 grand cheaper, and fractionally better mileage? sweet!
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meme 1:00PM (6/17/2009)
Ugh. Sam, I thought this site was learning better, and you posted an entire article based on fallacies. Primarily, that gasoline MPG and diesel MPGs are the same.
To reiterate what everyone here *should* already know, diesel is a denser fuel. It embodies nearly 15% more petroleum and releases nearly 15% more CO2 per gallon that you burn. And despite all of the PR efforts, it *is* still a much dirtier fuel. Modern diesel engines are far cleaner than old diesel engines, and often rival or beat old gasoline engines -- sure. But so are modern gasoline engines versus old gasoline engines. Modern diesel engines versus modern gasoline engines is a comparison way lopsided in favor of the gasoline engines. Show me, for example, a single commercial SULEV diesel.
30mpg gasoline is way better than 31mpg diesel.
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matt 1:22PM (6/17/2009)
I thought it was quite obvious to most people that the hybrid has far less emissions than the diesel. Not everyone who reads the site is concerned firstly with emissions... I for one am interested in future technology, efficiency and cheaper fuels for transportation... Lower emissions are a side benefit.....
wxman 5:12PM (6/17/2009)
Upstream emissions, both GHG and criteria pollutants, continued to be ignored here. GHG emissions from the refinery are just as bad as GHG emissions from the tailpipe.
According to MIT ("ON THE ROAD IN 2020: A life-cycle analysis of new automobile technologies" - http://web.mit.edu/energylab/www/pubs/el00-003.pdf - Table 2.4 on page 2-5), the gasoline fuel cycle emits over 600 MORE grams of GHG (CO2e) emissions per gallon that ULDS...
4.9 g C/MJ (gasoline); 3.3 g C/MJ (ULSD) --> 17.97 g CO2e/gal (gasoline); 12.1 g CO2e/gal (diesel)
125,071 BTU/gal = 131.96 MJ/gal (gasoline); 138,690 BTU/gal = 146.33 MJ/gal (diesel) (BTU content per EIA)
17.97 g CO2e/MJ X 131.96 MJ/gal = 2371.3 g CO2e/gal (gasoline)
12.1 g CO2e/MJ X 146.33 MJ/Gal = 1770.6 g CO2e/gal (diesel)
2371.3 – 1770.6 = 600.7 g more CO2e/gal for gasoline
Per EPA, 19.4 pounds CO2/gal (gasoline); 22.2 pounds CO2/gal (diesel)
19.4 X 453.6 = 8800 g CO2/gal (gasoline); 22.2 X 453.6 = 10,070 g CO2/gal (diesel)
8800 g/gal + 2371.36 g/gal = 11171.36 g effective CO2 emissions/gal (gasoline)
10,070 g/gal + 1770.6 g/gal = 11,840.6 g effective CO2 emissions/gal (diesel)
11840.6 ÷ 11171.36 = 1.0599 = 6% more CO2/gal for diesel
So, if my math is correct, diesel EFFECTIVELY has only 6% more CO2e/gal than gasoline, not the 15% that's quoted round here.
Furthermore, there are also upstream VOC emissions associated with gasoline production that are not associated with diesel fuel, something around 3 g/gallon, that are not included in the Tier 2 or LEV II regs. VOC/HC emissions are the problematic emission with respect to urban smog, not NOx.
meme 5:29PM (6/17/2009)
I've spoken with my father about this issue. He's the CEO of one of the US's largest refiners. According to him, that *used* to be the case, but isn't any more due to modern desulfurization requirements. If you'll look at your study, they get their energy consumption figures from reports from the 90s. It's out of date.
"VOC/HC emissions are the problematic emission with respect to urban smog, not NOx."
Are you kidding? NOx is *the* smog emission. It's what creates the stereotypical brownish "smog haze". VOCs are also bad, don't get me wrong -- but NOx *is* smog. And there's more emissions than just CO2, VOCs and NOx -- there's also SOx, PM, and CO.
wxman 9:15AM (6/18/2009)
I agree that more energy is required to desulfurize middle distillate to ULSD that to the higher sulfur diesel fuels, but it still doesn't eliminate the difference. The reference I cited specifically mentions that the ULSD requirement was taken into account. The Tier 2 light-duty vehicle regs were finalized in February of 2000, but the rule was drafted long before that.
Even Toyota acknowledges an energy advantage for ULSD over gasoline in a "well-to-tank" report they published in 2004 (http://www.mizuho-ir.co.jp/english/knowledge/documents/wtwghg041130.pdf - Tables 2.1.2 to 2.1.4).
>Are you kidding? NOx is *the* smog emission.<
No, I totally serious. NOx is *not* "the" smog emission, at least not in urban areas where non-attainment with the ozone NAAQS occurs almost exclusively.
Ozone is the primary constituent of "smog". All urban areas studied thus far are "VOC limited" with respect to ozone formation, meaning that reducing ambient NOx levels in these areas (at constant ambient VOC levels) will not only not reduce ambient ozone levels (ONLY redcutions in ambient VOC levels will), they have the potential to INCREASE them. This is known as the "NOx disbenefit".
I agree about the other pollutants, but PM has been essentially eliminated from diesel engines with particulate filters (DPF) and they're typically lower with respect to CO, and now even SOx since ULSD has lower levels of sulfur than gasoline in the U.S. (15 ppm vs 30 ppm)
I also meant to mention in my previous post that vehicles that meet SULEV aren't as common as you imply. Most gasoline vehicles are ULEV or even LEV. All of the "50-state" diesel vehicles currently on the market are ULEV, so there's no great difference there, especially if you include the upstream VOCs.
Sam 2:22PM (6/17/2009)
Ok all knowing people. How about you rent a Hybrid S400 and take it on the autobahn. Give it full throttle record your tank. Now do the same thing with the diesel. I can guarantee you that the Diesel will be using minimum 50% less fuel in that application. The tests to compare fuel economy are always baised toward gasoline engines but rarely compare real work fuel ecoconomy. Especially in germany.
When I last checked a BMW M3 driven behind a prius with wot actually got better gas mileage than the prius. Fact is they're not performance cars and driven in those situations the economy will suffer greatly.
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meme 3:12PM (6/17/2009)
What a real-world driving test -- flooring it on a track. :P
downtoearth 3:57PM (6/17/2009)
Sam:
> Ok all knowing people. How about you rent a Hybrid S400
> and take it on the autobahn. Give it full throttle record your tank.
> Now do the same thing with the diesel.
Why should anyone do this irrelevant test which will provide results having so little to do with reality?
This is a list of top speeds by country: http://en.wikipedia.org/wiki/National_Speed_Limits
Three countries IN THE ENTIRE WORLD allow going full-throttle. In Germany, 130 kph is the advised speed and you may have problems wih your insurance when causing an accident above this level.
> I can guarantee you that the Diesel will be using minimum 50% less fuel
> in that application.
This will happen only in case of old gasoline engines with no fuel efficiency boosting technology. The modern ones will perform much better.
http://bilder.autobild.de/ir_img/58157513_017599285a.jpg
220 kph = 137 mph,
Golf 2.0 TDI diesel = 16,4 l/100km = 611 MJ of energy/100km
Golf 1.4 TSI gasoline = 20,5 l/100km = 701 MJ of energy/100km
At 220 kph/137 mph a diesel car is 14,7% more efficient than Otto cycle gasoline engine car (hybrids run the more efficient Atkinson cycle).
130 kph = 80 mph
Golf 2.0 TDI diesel = 8,7 l/100km = 297 MJ of energy/100km
Golf 1.4 TSI gasoline = 6,7 l/100km = 250 MJ of energy/100km
At 130 kph/80 mph a diesel car is 19% more efficient.
100 kph = 62 mph
Golf 2.0 TDI diesel = 6,5 l/100km = 222.3 MJ of energy/100km
Golf 1.4 TSI gasoline = 5,6 l/100km = 208.88 MJ of energy/100km
At 100 kph/62 mph a diesel car is 6% more efficient.
80 kph = 50 mph
Golf 2.0 TDI diesel = 5,3 l/100km = 181.26 MJ of energy/100km
Golf 1.4 TSI gasoline = 4,6 l/100km = 171.58 MJ of energy/100km
At 100 kph/62 mph a diesel car is 5.6% more efficient.
Now estimate what percent of your mileage you cover at speeds above 100 kph = 62 mph (however, acceleration represents somewhat similar engine load as high speed driving).
Fuel energy densities taken from: http://en.wikipedia.org/wiki/Energy_density
> The tests to compare fuel economy are always
> baised toward gasoline engines but rarely compare
> real work fuel ecoconomy. Especially in germany.
This is utter nonsense that you failed to motivate. Spritmonitor.de readings for:
VW Golf 2.0 TDI diesel 140HP: 6,41 l/100km = 239 MJ of energy/100km (141 drivers)
VW Golf 1.4 TSI gas 140HP: 7,98 l/100km = 273 MJ of energy/100km (90 drivers)
So real life diesel cars efficiency advantage is 14,2%. People who are paid to lie about diesels say it is 35% advantage.
> When I last checked a BMW M3 driven behind a prius
> with wot actually got better gas mileage than the prius.
> Fact is they're not performance cars and driven in those
> situations the economy will suffer greatly.
This was a carefully biased test done by European journalists intentionally to depreciate Prius with its superior fuel efficiency and economy. It was done to protect their less efficient diesel cars from hybrids advantage. They run the Prius at top speed knowing that its powersplit device is optimized up to some 130 kph which is a top speed limit in the nearly entire world. Above this speed, Prius has to send some engine energy through its drivetrain electric path which decreases efficiency.
Real life Spritmonitor.de readings:
Toyota Prius II: 5,23 l/100km
BMW M3 E92: 13,47 l/100km
M3 uses 160% more fuel/energy.
wxman 5:34PM (6/17/2009)
>So real life diesel cars efficiency advantage is 14,2%.<
In the first place, you're using a specific example to conclude a generality, plus the example you cite is soon to be replaced by new engines...
"...the 1.2 TSI consumes 5.5 L/100km (43 mpg US), with 129 g/km CO2....
...The 66 kW variant is available in with the BlueMotion package. The resulting car offers fuel consumption is just 3.6 L/100km (65 mpg US), corresponding to a CO2 value of 96 g/km. In the standard version without BlueMotion package, the same engine consumes 4.2 liters (56 mpg US)...."
http://www.greencarcongress.com/2009/05/vw-vienna-20090514.html#more
4.2 ÷ 3.6 = 1.167 X 96 = 112 g CO2/mile for the NON-BlueMotion TDI
129 g CO2/mile (TSI) ÷ 112 g CO2/mile (standard version TDI) = 15.2% More CO2 emissions from TSI (not including upstream GHG emissions)
5.5 l/100 km (TSI) ÷ 4.2 l/100 km (standard TDI) = 1.31 ÷ 1.11 (11% more energy per gallon of diesel than gasoline per EIA) = 1.179 = ~18% more energy efficient on energy-equivalent basis, not including higher upstream energy usage for gasoline).
According to the National Academy of Sciences, diesel engines generally reduce fuel consumption by 30% - 40% based on their study of light-duty European diesels compared to 2007 light-duty gasoline European cars (NAS, “Assessment of Technologies for Improving Light Duty Vehicle Fuel Economy: Letter Report (2008)")
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Bill 10:11PM (6/17/2009)
$17,000 extra up-front means the hybrid never pays off.
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usbseawolf2000 10:57PM (6/18/2009)
Lexus hybrids cost less and they are much more refined (generations ahead).
usbseawolf2000 10:55PM (6/18/2009)
"When I last checked a BMW M3 driven behind a prius with wot actually got better gas mileage than the prius."
If the roles were to reverse, Prius would probably get 10x better MPG than the M3. It is how you drive as well as the car. If you accelerate WOT and hit the brakes, your MPG will be lower.
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