Why can't Americans have good, small diesels?
by Sam Abuelsamid on Oct 19th 2009 at 11:52AM 
2010 Volkswagen Golf TDI – Click above for high-res image gallery
T
he question is often asked, "Why is it that drivers in Europe can get all of these amazing high-mileage cars that get 50, 60 or even 70 mpg but we have to celebrate when we get half of that?" There are plenty of reasons, but one of the main ones is the remarkable compression ignition engine, more commonly known by the name of its inventor, the diesel. In recent years, diesel engined vehicles have accounted for over half of all new vehicle sales in Europe – in some places like France and Italy, up to 80 percent. Yet here in the United States, these high-efficiency wonders represent a tiny minority of car sales. Only in the heavy duty truck segment do diesels grab any significant attention. Read on after the jump to learn why so few diesel cars are available in the U.S.
Gallery: First Drive: 2010 Volkswagen Golf
Photos copyright ©2009 Sam Abuelsamid / Weblogs, Inc.
There are a number of reasons for limited diesel availability in the U.S. but the two primary hurdles are cost and emissions regulations. Diesel engines are inherently more expensive to build than spark ignition engines that run on gasoline or ethanol. Because of the way a diesel functions, the engine components need to be more robust to withstand the high internal pressures. However, the implementation of much tighter emissions standards has exacerbated the cost problem significantly.
The current U.S. emissions standards fall under what is known as Tier 2 and were phased in between 2004 and 2009. There are currently 8 bins, or categories, that new light duty vehicles can certified for, with bin 1 being zero emissions. California standards are even tighter and for a vehicle to be allowed to go on sale there it must meet the equivalent of at least the national bin 5 standard. Thus Tier 2 bin 5 (T2B5) is the de facto minimum for any automaker that wants to sell a car nationwide.
Here is where the problem lies. T2B5 has significantly tighter requirements than older EU4 European standards when it comes to particulate and nitrogen oxide emissions. The particulate or "soot" emissions are the black clouds that we're all used to seeing pour out of the exhaust of big trucks as they accelerate down the road. This problem has been largely addressed by the use of diesel particulate filters (DPF) in exhaust.
The particulate filter uses a ceramic core to trap the particles that make up the smoke. Pressure sensors on the inlet and exhaust sides of the filter are used to detect when it is full at which point regeneration takes place. To regenerate the filter, the air/fuel mix in the engine is adjusted to temporarily raise the exhaust gas temperature above 600 C, which causes the soot to burn off.
DPFs have been increasingly common installations in Europe over the last several years as the EU5 standard has gone into effect with a limit slightly lower than the T2B5 standard.
However, that is not enough to meet T2B5 requirements. For that we still need some additional exhaust after-treatment. Depending on the size of the vehicle, this can come in the form of either a lean NOx trap or urea injection (selective catalytic reduction). For the larger vehicles that are more common in the U.S., the urea injection systems are often the only way to go. This requires adding a storage tank for the urea solution that typically holds 4-8 gallons.
Depending on who you ask, the incremental cost of a Tier 2 Bin 5 compliant diesel over a similarly powerful gasoline engine can be $2,000 to $5,000. That's a hefty premium to overcome, especially when fuel prices are hovering at $2.50-2.75 a gallon. While a number of automakers including Honda, Kia and Nissan had indicated or announced outright they would introduce diesels to the U.S. market in 2009-10, all but VW, Mercedes and BMW have canceled or indefinitely suspended those plans.
Since mid-2008, when diesel prices spiked as much $1 a gallon more than gas followed by the economic collapse, all those automakers claimed that diesel just didn't economic sense here. Poor overall sales and the cost of certifying a new, low-volume powertrain mean that those looking for an affordable diesel are pretty much stuck with Volkswagen. So, the U.S. can get diesel cars, just not very many of them.
Thanks to David M. for the question.
Reader Comments (Page 1 of 4)
meme 12:46PM (10/19/2009)
You didn't bother to mention that a 50, 60, or 70mpg european diesel isn't really a 50, 60, or 70mpg diesel when it comes to the US. Due to the differences in cycles, it'll be rated more like 44, 52, or 61mpg. And have CO2 emissions more like a 38, 45, or 53mpg gasoline car, respectively.
Also, while the majorly eco-minded crowd is willing to accept the very slow accel times that the super-efficient diesels carry (like much of Europe is), the average US buyer isn't. So they usually up the power, which in turn drops that mpg rating further.
That said, we do deserve to have more selection in this market, so one can hope there will start being some more varied offerings in the US.
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Dino 1:29PM (10/19/2009)
This may not be entirely relevant to your point, Ray, but cars sold in different regions of the world are never exactly the *same car*. I'm not referring to which side the steering wheel is on, either. There would be no reason not to optimize performance for a regions given climate, driver types, etc, and I can tell you first hand that manufacturers definitely do this.
Regarding the topic (which is getting a little overdone at this point, no offense to the author), the question(s) I would like to see answered is:
Why is T2B5 just out of reach of what can be done without aftertreatment? Is that incremental difference in emissions significant to the environment in the case of small passenger cars?
lne937s 1:33PM (10/19/2009)
http://www.fueleconomy.gov/feg/byclass.htm
Good point on the CO2. Diesel contains more carbon per gallon and more carbon per BTU of energy.
For example, Jetta Diesel tests for 63 mpg in the UK highway test gets tests at 41 mpg here.
Its US carbon footprint of 6.2 tons CO2/year works out to be worse than a lot of regular gasoline vehicles in the same class, much less a Prius at 3.7.
Sam Abuelsamid 1:58PM (10/19/2009)
Here on ABG we always quote mileage numbers in miles per US gallon regardless of how the test was done. We also try to mention the relevant test cycle. For example the EU or Japanese 10-15 cycle which is far more unrealistic than the Euro cycle.
Given that, cars like the Smart ForTwo CDi is rated at 71 mpg (US) and the Fiesta ecoNetic is above 60 mpg (US)
As for the Jetta, that 63 mpg in imperial gallons which equates to 52 mpg (US). While that is well above the EPA 2009 rating of 41 mpg (up to 42 mpg for 2010), it is not uncommon to get 50+mpg on the highway in the real world with a Jetta.
The EU cycle may overestimate mileage, but real world experience indicates that the EPA underestimates diesel mileage by 10-15% or more.
As for CO2, diesel fuel does contain more carbon than gasoline, (about 15%) but diesel engines are on average 30% more efficient than a similarly powerful gas engine and thus emit about 25% less CO2.
meme 3:32PM (10/19/2009)
"Here on ABG we always quote mileage numbers in miles per US gallon regardless of how the test was done."
That's a straw man; I never raised the issue of US gallons vs. imperial gallons. I raised the issue of different drivecycles.
And yes, the 10-15 cycle is even worse than the NEDC, but the NEDC is still worse than FTP-75/US06
"As for the Jetta, that 63 mpg in imperial gallons which equates to 52 mpg (US). While that is well above the EPA 2009 rating of 41 mpg (up to 42 mpg for 2010)"
Which is exactly what I said, only worse. I suggested 50mpg "US" NEDC = 44mpg "US" EPA. The actual, in this case, is 52 mpg "US" NEDC = 42 mpg "US" EPA.
Given that you apparently *know* that NEDC numbers are higher than our numbers over here, why didn't you bother to mention that in your article on why we can't get cars with these extremely high mileages over here?
", it is not uncommon to get 50+mpg on the highway in the real world with a Jetta."
Sorry, but we use drivecycles for a reason: to eliminate the differences in personal driving habits. Now, if you think you have discovered a *reason* for systemic bias in the FTP-75 and US06 drivecycle, submit it to the EPA, and if it passes review, *then* I'll care about your anecdotal claim. As it stands, I'd be willing to put money on you seeing heavy selection bias.
"As for CO2, diesel fuel does contain more carbon than gasoline, (about 15%) but diesel engines are on average 30% more efficient than a similarly powerful gas engine and thus emit about 25% less CO2."
Irrelevant. That's already factored into the mpg numbers. The CO2 difference is not, so it still needs to be canceled out. The greater efficiency of diesels is why they get better numbers than non-hybrid gasoline vehicles even after the CO2 difference is factored into account. It doesn't excuse the fact that you still need the CO2 difference factored into account.
Matt 3:12PM (10/20/2009)
My personal opinion, not to be confused with facts:
The reason the NOx numbers are set so low in California is that the government in that state does not like photochemical smog looming in what would otherwise be a beautiful place. "Photochemical smog is the chemical reaction of sunlight, nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the atmosphere." It is bad for the health of the residents, but it's worse for economic development of cities. The end.
Oh, and meme. Youyou need to lay off bashing Sam's comment. Picking apart someone's comment line by line makes your rebuttal seem childish, like your feelings were hurt or something. As for the "real world" consumption figures, I actually agree with Sam, government agencies ESTIMATE fuel consumption based on a short series of standard tests. Those tests do not account for feedback from the vehicle (throttle response, engine noises, etc.) that contribute to real driver input. That is, what is achieved in a standard test is not necessarily what is achieved by the average owner of a particular model.
I propose that all of the current government test cycles be scrapped. What we need instead is a range of fuel consumption. We need consumption at an average highway speed to show aerodynamic and drive train efficiency, and we need a 0-60-0 test for consumption at a reasonable acceleration combined with any regenerative capabilities. THEN, we need a maximum efficiency number at a low highway speed (maybe 45 mph) and a minimum efficiency at a high interstate speed (maybe 80 mph). Do something similar with the accel/decel test (full throttle and full brake, then very light throttle and very light brake). What you'd end up with is two simple graphs showing max, min, and average fuel economy. Dumb people will still be able to look at the average numbers and choose without additional thought. People who know their driving habits will be able to discern which car is better for them based on their own driving style and commute. I don't see this creating a lot of extra work for the EPA or other agency since the testing cycles we currently have are much more complicated. I'll bet they have most of these numbers already, why not publish them somewhere?
naturalyshocked 5:53PM (10/21/2009)
@Matt
californaria closed the well, after the cow fell in to it.
it's rediculous the united states didn't raised taxes on gasoline a decado ago, like they did in the netherlands, a mere 25 cents on top on the next day.
why does the US permit use carburators?
germany doubled the circulation tax on all cars who don't have a catalitic converter more than 20 years ago.
the problem would have solved it self a long time ago.
why do the american think always their system is superior over the european system?
witch is roughly 13x older than new york.
germany has the TUV
http://en.wikipedia.org/wiki/Technischer_%C3%9Cberwachungsverein
witch the world's most advanced Technical Inspection Association.
i'm sure about 80% of all people on the world have seen their logo on somekind of comsumer product.
witch is an INDEPENDENT consultant.
than you have the ADAC, the drivers club, with is also the worlds most advanced Association in their territory.
http://en.wikipedia.org/wiki/ADAC
both test same cars, how can both associations be so wrong according to americans?
the world biggest exporter.
yes, they sell more then you with 305 million habitants.
how can the rules be so strict if the domestic builders mostly offer v6 in their models?
i live in a city with close to 800.000 habitants and about 80% or maby more is HDI/TDI/etc engined. i can't say if i realy smell the cars.
don't act like the world's police officer, trying to be the example, meanwhile avoiding the koyoto act, because you don't like the develping economy's have less stricter of rthe present time.
in other words you're still somewhat a develping economy?
when i had my 90ps tdi mkIV golf, 10 years ago, i payed attention when i had a long road trip.
volkswagen's statement was correct, 1000km on 50 liter diesel.
i never fill up my tank, i always use 1 10 euro bills.
i could travel significantly more than my previous 1600/2000 cc gasoline cars.
ok, a litle less topspeed, but nevertheless sporty rapid in city traffic.
witch is no doubly way more agressive than yours.
p.s. i'm trying to have a neutral view on things, i'm not with you nor against you.
i just say thing as it is.
Mohannair70 1:37PM (10/19/2009)
GM India has launched its Chevy Cruze in India with a 2.0 liter diesel engine. which makes about 150hp and 327Nm of torque.
Its supposedly does 14 km to a liter in city which is about 32 mpg and 18.3 km to a liter on highways which is 43.4 mpg
Why cannot GM sell this car here in the US? This car is going to be sold with similar diesel engine in Europe too !!!
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wincros 12:18PM (10/19/2009)
Good article.
Maybe it should be followed by "Why Can't Americans have fun to drive hybrids?" or "Why Americans who like cars and driving will continue to buy gasoline internal combustion engine cars".
Saw an actual Tesla this weekend by the front door in the parking lot at Whole Foods. Lovely car. Ironic though. It drew no interest at all from that organic crowd. Smaller than I thought it would be.
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Lad 1:37PM (10/19/2009)
One thing missing in all this: many people buy their cars to last over five years. I still drive a '97 Volvo. So the dilemma is "Should I buy a fossil fueled car now or wait for the BEVs that offer the promise of less complexity, less maintenance cost, less fuel cost, etc? You see all the news is about the gloom and doom of running gasoline and diesel cars and the outlook for returning to cheap oil is bleak; so...would one who keeps cars over 10 plus years take a chance on buying an obsolete diesel/gasoline driven car or opt to wait on the electric cars?....I'll wait thank you!
Boyprodigy1 3:26PM (10/19/2009)
@lad
The tesla roadster has 8 moving parts in it
It has a battery pack in it which has 6,831 battery cells which are hooked up to a computer management system which tells you specifically when a cell goes out
The battery system has a temperature/ charging management system which heats and cools the battery and makes sure that it doesn't get over charged or over drained.
That battery pack hooks up to an AC inverter which then pushes the electicity to a 3-phase, 4-pole electric motor pushing 248 hp and 200lb ft of torque (At 0 rpm all the way up to 6000 rpm)
The Tesla roadster has a single gear, no clutch and no shifting
The Tesla roadster is probably the most complex electric vehicle you can buy and i just built it for you in this post. Could you do that with an ICE car. Doubt it. What the hell are you smoking... Psh more complex...
P.S. Woops i forgot the washer fluid...
Lad 4:13PM (10/19/2009)
@Boy...:
I think your post and mine are speaking in the affirmative for electric cars; but, I'm not sure because of your negative remark which adds nothing to you facts or point.
Boyprodigy1 4:33PM (10/19/2009)
@ lad
wow... its a monday. sorry.
Serge 12:28PM (10/19/2009)
Excellent primer on the topic, Sam. Thanks!
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raygundan 12:59PM (10/19/2009)
It doesn't hurt that the UK gallon is larger, or that the EU fuel-economy test returns consistently higher numbers than the current US/EPA tests. Bring the same car to the US, and giev it the EPA tests, and it won't get 70mpg anymore.
Adjusting for the difference in gallons alone drops the number by 17%.
70mpg (UK) = 58mpg (US), and this ignores the test differences.
Similarly, the tests are different. Take the 2010 Toyota Prius, which is essentially identical in all the markets it is sold in. In the US, it is rated at 50mpg. In the UK, it is rated at 72.4mpg. The difference between ratings, owing to both the different gallon and the differences in testing, is more than 30%. This is the *same car*. This is why we don't see 70mpg cars in the US. They wouldn't *be* 70mpg cars here.
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PowerCell 2:55PM (10/19/2009)
A US gallon is 20% larger than an Imperial gallon... you have it backwards.
Phil L. 2:38PM (10/19/2009)
PowerCell -
No it isn't. You've got it backwards.
Google "1 imperial gallon in US gallons" and you'll get:
1 Imperial gallon = 1.20095042 US gallons
I love Google for unit conversions.
Boyprodigy1 3:40PM (10/19/2009)
lmgtfy.com/?q=conver+ imperial+gallon+to+UK+gallon
yes i feel like being a smartass
wincros 3:47PM (10/19/2009)
Sometimes you get lucky and get a list like this, from this site:
http://green.autoblog.com/2009/10/02/report-all-of-europes-15-most-fuel-efficient-cars-get-better-t/
It includes a Prius for comparison purposes with mostly small diesels getting near and better than the fuel economy of the hybrid.
Laurens 1:24PM (10/19/2009)
We should find similar regulatory measures to ban hybrids in Europe ;-) Any suggestions?
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