Diesel vs. Hybrid emmissions compared

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Wanna TDI

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Any one care to comment on this quote from a hybrid chat site:

Sorry but as far as I can see "clean diesel" is nothing more than marketing hype. Right up there with "clean coal". It may be cleaner than it was, but thats not really saying much. I am really concerned that people are buying this hype and honestly believe their new diesel is going to save the world. Its kind of sad to see Honda and Toyota heading down that path as well. Lets take a look at how the emissions on a few "new" diesels stack up:

2008 Mercedes E320 Bluetec vs. 2007 Toyota Camry Hybrid
CO2 (g/mi): 387.85 vs. 258.47 (50% higher) Greenhouse/Global Warming Gas
CO (g/mi): 2.88 vs. 0 (inf higher) Poison / Toxic
NOx (g/mi): 0.165 vs. 0.01 (1550% or 16.5X higher) Smog / Acid Rain
NMOG (g/mi): 0.0814 vs. 0.006 (1257% or 13.6X higher) Formaldehyde & other VOCs, irritant, cancer
PM (g/mi): 0.002 vs. 0 (inf higher) asthma, lung development problems in children

2008 VW Toureg Diesel vs 2007 Lexus RX400h 4WD
CO2 (g/mi): 593.18 vs. 338.0 (75.5% higher) Greenhouse/Global Warming Gas
CO (g/mi): 0.08 vs. 0 (inf higher) Poison / Toxic
NOx (g/mi): 0.57 vs. 0.01 (5600% or 57X higher) Smog / Acid Rain
NMOG (g/mi): 0.0176 vs. 0.007 (152% or 2.5X higher) Formaldehyde & other VOCs, irritant, cancer
PM (g/mi): 0.007 vs. 0 (inf higher) asthma, lung development problems in children

2008 Jeep Grand Cherokee 4WD Diesel vs. 2008 Toyota Highlander Hybrid 4WD
CO2 (g/mi): 530.74 vs. 338.0 (57% higher) Greenhouse/Global Warming Gas
CO (g/mi): 0 vs. 0 (even) Poison / Toxic
NOx (g/mi): 0.4 vs. 0 (inf higher) Smog / Acid Rain
NMOG (g/mi): Not Reported vs. 0.008 Formaldehyde & other VOCs, irritant, cancer
HC-NM (g/mi): 0.006 vs. 0.001 (500% or 6X higher) hydrocarbons, water pollution, ground ozone, smog
PM (g/mi): 0.007 vs. 0 (inf higher) asthma, lung development problems in children

2008 VW Jetta TDI
Failed meet minimum emissions requirements, being revised

2006 VW Jetta Wagon TDI vs. 2006 Toyota Prius
CO2 (g/mi): 305.58 vs. 191.04 (60% higher) Greenhouse/Global Warming Gas
CO (g/mi): 0.11 vs. 0.1 (10% higher) Poison / Toxic
NOx (g/mi): 0.55 vs. 0.01 (5400% or 55X higher) Smog / Acid Rain
NMOG (g/mi): 0.0123 vs. 0.009 (37% higher) Formaldehyde & other VOCs, irritant, cancer
HC-NM+NOX-COMP (g/mi): 0.824 vs. 0.03 (2647% or 27.5X higher) composite of main smog ingredients
PM (g/mi): 0.069 vs. 0 (inf higher) asthma, lung development problems in children

What I found most surprising in this analysis was that the Camry, Highlander, and RX400h are all actually cleaner than the Prius (ignoring CO2)! I assume this is just a matter of newer tech, as Prius was a few years older design wise. Hopefully next rev will see the same improvements. The other interesting thing was how bad the Vue Hybrid looked compared to the Escape.

2007 Saturn Vue Hybrid vs. 2007 Ford Escape Hybrid
CO2 (g/mi): 338.0 vs. 292.93 (15% higher) Greenhouse/Global Warming Gas
CO (g/mi): 2.4 vs. 0.1 (2300% or 24X higher) Poison / Toxic
NOx (g/mi): 0.04 vs. 0.02 (100% or 2X higher) Smog / Acid Rain
NMOG (g/mi): 0.062 vs. 0.006 (933% or 10.3X higher) Formaldehyde & other VOCs, irritant, cancer
HC-NM+NOX-COMP (g/mi): 0.05 vs. 0.01 (400% or 5X higher) composite of main smog ingredients

All emissions data is from:
Annual Certification Test Results & Data | Cars and Light Trucks | US EPA
Wherever possible, federal test data at 120 or 150k miles has been used for a fair comparison. CO2 g/mi is calculated from 2008 calc EPA composite mileage using the EPA/DOE conversion factors of 8788 g/gal for gasoline and 10084 g/gal for diesel. These can be found here:
Emission Facts: Average Carbon Dioxide Emissions Resulting from Gasoline and Diesel Fuel | US EPA

Biodiesel helps somewhat, but not nearly as much as people seem to think. It seems like every day I hear some yahoo claiming his H1 running biodiesel has no emissions. According to this data:
http://www.biodiesel.org/pdf_files/f.../emissions.pdf
It reduces most pollutants by about a factor of 2 (not counting NOx which gets slightly worse). Given that many of the diesels above are often worse by a factor of 10-20, that doesn't really even put a dent in the problem. There is also not much basis for the carbon nuetral claims. That _may_ be true if you make your own bd from waste veggie oil using no energy. Sadly we don't eat nearly enough french fries to run all our cars this way. Large scale vegatable oil production will probably require sources like the plam plantations of SE asia, which are an environmental disaster in the making. If its 3X cheaper than American corn or soy bean oil, what do you want to bet thats what people will go with?
Palm oil: the biofuel of the future driving an ecological disaster now | Special reports | Guardian Unlimited

I would really like to be wrong about this. I really want to convert my Land Rover to Diesel and run it on bio. Can't quite seem to rationalize it based on these numbers though.
 

Joe_Meehan

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You really can't compare diesel to gas emissions as they are good at different things. It is apples and oranges.
 

4Gman

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Wanna TDI said:
Any one care to comment on this quote from a hybrid chat site
Looks like a bunch of self serving BS distorted statistics. I hope you dont honestly believe this hybrid hype.

This "analysis" coincidentally does not include many factors.
One big example: The much more harmful gasoline vapors associated with gas vehicles.
 

GoFaster

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The CO2 emission figures are somewhat suspicious and may be based on EPA test figures, which have had a history of over-inflating the benefit of hybrid powertrains.

Example, in "real world driving by real everyday people (NOT hypermiling)", fuel consumption of a Jetta TDI and of a Prius are comparable. (In US figures, most people report 45 mpg or thereabouts from both vehicles.) The CO2 emissions of the Jetta ought to be about 10% more on account of the higher carbon content of the diesel fuel - not 60% higher.

It's true that some gasoline engines are passing the current emission regulations by a large factor. But it's absurd - albeit true - to say that the PM emissions of a diesel are "infinitely" higher than those of the hybrid on account of the PM emissions of the hybrid in question being below the detection limit (I REFUSE to accept that the particle emissions will be zero!!). The PM content of quite a number of DPF-equipped diesel vehicles has been reported as being lower than the PM content in the air going into the engine. When emission controls have progressed to the point where the regulated nasties coming out the tailpipe are less than those of the atmosphere, is it not time to stop being concerned about that particular emission?

To put this into perspective, 0.069 grams per mile of PM from a 2006 Jetta TDI (without DPF) works out to 6.9 kg of total PM emissions over a distance of 100,000 miles. Most likely, that same vehicle will emit more PM from its *tires* during that time. When the vehicle gets to the end of its useful life, more PM will be emitted from the process of squashing and shredding it and (in many cases) burning the leftover plastic materials that can't be recycled.
 

TurbinePower

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GoFaster said:
It's true that some gasoline engines are passing the current emission regulations by a large factor. But it's absurd - albeit true - to say that the PM emissions of a diesel are "infinitely" higher than those of the hybrid on account of the PM emissions of the hybrid in question being below the detection limit (I REFUSE to accept that the particle emissions will be zero!!). The PM content of quite a number of DPF-equipped diesel vehicles has been reported as being lower than the PM content in the air going into the engine. When emission controls have progressed to the point where the regulated nasties coming out the tailpipe are less than those of the atmosphere, is it not time to stop being concerned about that particular emission?
Isn't the latest cancer/carcinogenic PM research showing that it's those tiny subfine and ultrafine particulates that are really doing the damage anyway? IE what gas vehicles have been emitting all the time?

I get dizzy pumping gas. I don't get dizzy pumping diesel. I don't even realize when I'm pumping biodiesel...
 

kilo69

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DId they not take into account the manufacturing of the hybrid's battery and electronic systems?

hybrid's are never going to be better... it's either going to be electric cars with clean sources of power or something we haven't even seen yet.

Remember a pure electric car doesn't need engine coolants, lubicants and greases.

I'm happy with my TDI choice, maybe I should make a TDI/hybrid :p
 

Dan_Ruddock

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Absurd!! for some people if the thing runs on a fossil fuel it will never be clean enough and unless the current measuring equipment says the emissions are zero then god forbid using it on the road. If we really want to clean up the air why don't we go after the real problem which is old cars, big rigs and heavy industry. For some CARB politicians they justify there usefulness by coming up with the latest overkill standards. Maybe they should spend there time coming up with ever more demanding fuel mileage standards which would service the public in a useful way. Dan
 

wandlc

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I would take any EPA equation with a grain of salt. The mandated equation used to calculate g/mile driven of NOx emissions is not even stoiciametrically balanced, which means garbage in garbage out. The numbers it generates are meaningless. Also, where are the byproducts of combusting all of the additives in gasoline. Has anyone seen any numbers for the byrpoduct of combusting MTBE? No, you won't find them. The additives in gasoline are generally not very nice to the environment, but they are never monitored. MTBE is very difficult to clean up, yet was mandated by the very EPA that is responsible for establishing emissions numbers for all vehicles. It brings up the old saying "Figures don't lie, liars figure".
 

wxman

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Many good points already brought up.

Here are a few more...

According to NREL, many of the hybrids typically operate in the all-electric over much of the FTP75 driving cycle. Thus they spend a considerable amount of time emitting NO pollutants in the FTP75 test.

Toyota concedes that there is more energy required in the materials production stage for its hybrids (they take more energy to produce than a Hummer!).

Granted, direct emissions from PZEV vehicles are probably extremely low, but these hybrids still require GASOLINE as a fuel. Gasoline is an extremely volatile substance. A recent study shows that between 71% and 80% of ambient NMHC in Southern California (SoCAB) comes from GASOLINE vehicles (confirming an earlier study by NREL), and of that 33% is external to the vehicles themselves, i.e., fugitive VOC emissions during the production, storage, and distribution of gasoline. Thus even PZEV vehicles contribute to these emissions.

I also agree with GoFaster that direct PM emissions from gasoline vehicles (even hybrids) isn't zero, and that using a particle number emissions metric is a more appropriate way of evaluating PM emissions.

 

GoFaster

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That photo above, on its own, is a good reply to the gasoline-hybrid-and-nothing-else people who think their hybrid vehicle is the ultimate solution to everything.
 

tsingtao

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A new chain of markets, Fresh and Easy, opening up in California and Arizona, has special Hybrid parking spots right up front next to the handicapped spaces. I suggest everyone go to their website and let them know what they think about this.
 

bakerinva

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Yeah, have seen what tsingtoa is talking about...AND in California (Bay Area at least) if you have a hybrid, you can drive in the carpool lane on the highway (or HOV lane as we call them in Virginia) even if you are the only person in the car!!! ***??? There are TDIs out there who get better economy than most hybrids, yet unless they have 3 people, they have to stop and go like everyone else!!! Not only that, when a hybrid is running at highway speed, it is running the gas engine, just like nearly every other vehicle!! It makes NO SENSE!
 
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tsingtao

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bakerinva said:
Yeah, have seen what tsingtoa is talking about...AND in California (Bay Area at least) if you have a hybrid, you can drive in the carpool lane on the highway (or HOV lane as we call them in Virginia) even if you are the only person in the car!!! ***??? There are TDIs out there who get better economy than most hybrids, yet unless they have 3 people, they have to stop and go like everyone else!!! Not only that, when a hybrid is running at highway speed, it is running the gas engine, just like nearly every other vehicle!! It makes NO SENSE!
Yes, they also started that nonsense here in Arizona. As soon as they let hybrids in the carpool lane their sales took off. They get a blue license plate with clouds (to symbolize a clean sky) that says "Alternative fuel Vehicle." What garbage!. It's all feel good run amuck.
 

KentSzabo

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According to www.volkswagen.de the Golf with a 1.9 TDI produces 132 g/km of carbon dioxide this is 212.432 g/mi. Therefore all of the TDI's running around the U.S. today are more carbon conservative than the hybrids mentioned above. Also the above site states the Golf BlueMotion produces 115 g/km or 185 g/mi.
 
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KentSzabo

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That bogus figure of 191 g/mi for the 2006 Toyota Prius above was based on the old EPA mileage figure of 55 mpg. The reality of it is the new EPA mileage figure is 16% less, therefore the carbon dioxide emmisions goes up to 222 g/mi.

This information comes from www.fueleconomy.gov

2006 Toyota Prius

Automatic (variable gear ratios)
4 Cylinders
1.5 Liters
Regular Gasoline​

Hybrid Vehicle

New MPG tests are more realistic
New EPA MPG
Old EPA MPG
48 City 46 Combined 45 Hwy 60 City 55 Combined 51 Hwy



 
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Peakoilride

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options

This is a great topic and discussion...Diesels obviously pollute more than gas engines, you can't argue about that. People also are buying into the hype about both diesels and hybrids (I am one of them). I went to school and studied environmental science for 4 years and the tdi was my car of choice. Although I haven't done anything to "save the world" with my diesel yet, I now have some options to do so. In my case I am defining world saving as an end to US armed foreces in say Iraq. Which to me is saving the world even if it's only a few thousand American kids and 50,000 Iraqis. World saving can also be defined in this oil reltated discussion as you ment it in terms of minimizing harmful emissions...Anyway these are the options I see. Fill up with some domestic made bio-diesel or convert your car to run on vegetable oil (lets see the emissions on that). I could be wrong, but I bet that burning vegetable oil produces less pollutants than gasoline. The thing about the hybrid is this. It uses gasoline and batteries. I have heard about the kits to make hybrids all electric, but you still would be plugging into the grid which is mostly powered by good old coal. That is the only option i see with the hybrid in terms of world saving. Those things are going to keep burning gasoline, so nothing has changed.

In conclusion, you should convert your Land Rover to diesel,ride a bike or walk more often, buy alternative fuels, and you have "saved the world" in the sense that you do not need to feel guilty for driving war and maybe global warming.
 

nortones2

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Re "Diesels obviously pollute more than gas engines, " this is not so. Reread what Go Faster and turbine have posted. You might bear in mind that for particulates, the mass emissions are weighted against diesel, no doubt deliberately, in the cited figures. But the numbers of UFP are as great from gas engines: its just not measured, partly because the techniques have not been widely available and the role of UFP had not been identified until recently.
 

wxman

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Peakoilride said:
This is a great topic and discussion...Diesels obviously pollute more than gas engines, you can't argue about that....
With all due respect to a fellow environmental scientist, I'm not willing to concede that even with respect to the old Tier 1 diesel vehicles, much less the T2B5 diesel vehicles whenever they get here (in general anyway).
 

Peakoilride

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Compare Cars

okay, goto the government web site on fuel economy and compare say a 2005 tdi to a 2005 Prius. It compares economy and air pollution. I know it doesn't show enough information for some of you, but the tdi gets a 1 and the hybrid gets an 8 with 10 being Good and 1 being Bad on the air pollution scale. Also I suggest you guys learn about the refining process of crude oil and notice that diesel is heavier than gasoline and some of that weight comes out the tail pipe and floats around the air...and those black particulates that cover the back of my tdi are a pretty good sign that diesel burns more dirty than a gas car...Particulates kill

http://www.fueleconomy.gov/feg/sbs.htm
 

Joe_Meehan

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Peakoilride said:
...Diesels obviously pollute more than gas engines, ...
Are you making a joke? If by "more" you mean weight, maybe that is correct, but soon to change. If you mean create more of a problem, then I would have to disagree.

It is not really possible to compare the damage done from the pollution of the two types. The have different pollution profiles. Apples and Oranges.
 

wxman

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Peakoilride said:
...Also I suggest you guys learn about the refining process of crude oil and notice that diesel is heavier than gasoline...
Actually, that is one of the biggest reasons why gasoline vehicles have a relatively high adverse environmental impact. Gasoline is an extremely volatile substance. A recent study in Southern California shows that about 1/3 (between 31% and 34%) of ambient NMHC is from evaporative emissions EXTERNAL to the vehicles itself (Steven G. Brown, Anna Frankel and Hilary R. Hafner; “Source apportionment of VOCs in the Los Angeles area using positive matrix factorization”. Atmospheric Environment, Volume 41, Issue 2, January 2007, Pages 227-237). Overall, gasoline vehicles are responsible for about 80% (!) of ambient NMHC (22%-24% from exhaust, ~25% from evaporative emissions from the vehicle itself), but even if vehicle NMHC emissions are reduced to ZERO (i.e., ZEV or Bin 1), they’ll still be responsible for ~33% of the ambient NMHC just from the handling of the fuel they require (biogenic VOCs only account for 1%-3% of the ambient NMHC in Southern California). NMHC not only is the primary contributor to ground-level ozone (smog), it oxidizes to increasingly lower vapor pressure oxidation products…forming secondary particulate matter (SOA). Most of this PM is ultrafine and/or nanoparticles.

Furthermore, many source apportionment studies have shown that GASOLINE vehicles are responsible for a much larger contribution of direct PM.

In Denver (North Front Range Air Quality Study):



From a source apportionment study in Washington, D.C. (Eugene Kim, Philip K. Hopke; “Source Apportionment of Fine Particles in Washington, DC, Utilizing Temperature-Resolved Carbon Fractions.” Journal of the Air & Waste Management Association, Volume 54, July 2004, Pages 773-785):



Note that these predate widespread use of DPF; relative contribution from diesel will continue to decline as older diesel vehicles are replaced by the new clean diesels.
 
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tdisedanman

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Nothing commercially available is clean at this point. I see they conveniently left out pollution caused in production and disposal of those huge batteries. There are many sides to a coin.
 

hevster1

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Since when don't gas engines give of CO? I am a licensed inspector for gods sake and I am Toyota Hybrid certified. That is the nature of the beast. When we were still doing IM240 or ASM 50-15 tests hybrids were exempt as they would run in electric mode OR start up and cause a failure.
Hybrids are NOT the answer and they never will be. They are a way for Toyota and other companies to say they are "green" (I hate that f**king term, it is used way to much and is meaningless) while making money hand over fist.
That said Diesels do pollute, probably more than a gas car. Will it change with the new breed? Time will tell. However, they are probably a better answer for 95% of the drivers out there as a compromise for real world power and economy.
The battery issue is far less of a problem than people think. Very few have been replaced since the Prius was imported.


Easy way to stop air pollution, Every politician cannot breathe for 1 hour.
 
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Dan_Ruddock

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Here is a question that is never asked. When are cars (gas or diesel) clean enough? The earth has an amazing ability to clean it self. If this question is not answered by those who make the rules an economy car will cost 30k plus. Dan
 

GoFaster

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Therein lies the problem - and it's an issue with society as a whole. Nobody likes bad things happening to anybody. Fair enough. But the consequence is that no amount of pollution is small enough, no level of noise is quiet enough, no machine is safe enough. The trouble is that risks and bad side effects can never be totally eliminated from any human endeavour. The sense of balance and reasonable trade-offs has gone out the window.

To add to hevster1's suggestion, I would also suggest that a good number of product-liability lawyers need to stop breathing for an hour.
 

nortones2

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tdisedanman said:
Nothing commercially available is clean at this point. I see they conveniently left out pollution caused in production and disposal of those huge batteries. There are many sides to a coin.
The Prius has 168 1.2v cells, in a pack weighing 99lbs. The cells can be removed individually if defective, and the whole set can be recycled. Pollution? Only in the propaganda re Sudbury, Ontario, which is just one of many facilities producing nickel, the vast majority of which goes into mundane items such as spoons! Homework required before spouting, perhaps?:rolleyes:
 

TurbinePower

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GoFaster said:
To add to hevster1's suggestion, I would also suggest that a good number of product-liability lawyers need to stop breathing for an hour.
Better play it safe and make it two hours... ;)
 
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