Particulate matter (PM) from on-road diesel engines (including heavy-duty) really is a non-issue starting in 2007. The U.S. regs will effectively mandate use of PM filters which are clearly very effective. Studies have shown that PM from light-duty diesel vehicles are less than PM from low-emitting gasoline vehicles in terms of both mass and number. Even diesel-hating CARB has acknowledged this.

I knew this topic would make for a lame thread.

Michel just a delivery driver that drives 1500+ miles a week 30 weeks a year. That plus personnal driving, probably closer to 60,000 - 65,000 miles a year. Yuck!

Studies have shown that PM from light-duty diesel vehicles are less than PM from low-emitting gasoline vehicles in terms of both mass and number.

Link?

Hi,
a diesel is a very expensive engine due to the sophisticated injection system. It has its place no doubt, but it has to run as much as possible.
In a plugin hybrid with lets say 40km electric range (that is the range in Germany for 90%of all drivings) it runs only 10%of time in long range modus.
For this 10% its better to install a cheap, light weight optimized ICE, maybe easily removable ;-), but not a hightech diesel.
German (from Volkswagen diesel country.)

Hi,
a diesel is a very expensive engine due to the sophisticated injection system. It has its place no doubt, but it has to run as much as possible.
In a plugin hybrid with lets say 40km electric range (that is the range in Germany for 90%of all drivings) it runs only 10%of time in long range modus.
For this 10% its better to install a cheap, light weight optimized ICE, maybe easily removable ;-), but not a hightech diesel.
German (from Volkswagen diesel country.)

Link?

http://www.findarticles.com/p/articles/mi_m0CYH/is_5_7/ai_99232199

See also:

http://www.dieselforecast.com/ArticleDetails.php?articleID=263
http://www.akpf.org/pub/2002_eth_summ.pdf
http://www1.eere.energy.gov/vehiclesandfuels/pdfs/deer_2003/session9/2003_deer_storey.pdf
http://www.usea.org/G8%20proceedings/Hofbauer-Pr%C3%A4sentation1-USE%20THIS.pdf
http://www1.eere.energy.gov/vehiclesandfuels/pdfs/deer_2003/session9/2003_deer_kittelson.pdf
http://www.dieselnet.com/news/2004/12bosch.php

That third link is good -- lots of detailed data from a real-world test. Thanks.

from the first link (which is from "Diesel Fuel News"):

However, the PSA car doesn't meet LEV-2 or EPA Tier 2/Bin 5 emissions limits for nitrogen oxides (NOx). As one California Energy Commission (CEC) official commented to us following the SAE presentations, U.S. EPA calculates that the PSA car "emits NOx at 0.6 grams/mile versus 0.08 g/mi as required in the U.S." So -- assuming a possible NOx/PM emissions technology trade-off -- if a similar clean-diesel car were to hit upcoming EPA/CARB ultra-low-NOx limits, then PM emissions might be "around 5 mg/mile or less for diesel, based on the Toyota DPNR results," this CEC official told us, citing EPA estimates.

The article is also over 3 years old, as evidenced by this sentence:
These PSA cars emit about 0.5 milligrams/mile of PM, versus about 2 mg/mile PM from advanced gasoline cars, he said.

Bins 2 through 6 allow a maximum of 10 mg/mile. This person isn't even getting his decimals in the right place. What he meant to say is that the PSA cars (per his claim) are getting 5 mg/mile (or as its put in normal lingo, 0.005 g/mile) compared to the maximum .01 g/mile for most current gasoline vehicles, not the "advanced gasoline cars".

Mahindra & Mahindra, an Indian automaker, going to try to sell SUVs and pickups in the US, through an American distributer, Global Vehicles USA. It plans to release a diesel electric hybrid version of their mid size Scorpio SUV following their US debut. Sources claim that the 2 ton SUV will achieve 30-35 mpg.

Martin wrote: Sorry George, though as an asthmatic doctor you might expect me to agree with you I think you're way off. First, when I worked in what Americans would call the ER, I never saw anyone who came in dying of *particulates* ...

They don't come into the ER with the word "particulates" on their forehead, but some of the cardiovascular and pulmonary M&M that you saw may have been aggravated or induced by particulate pollution. Epidemiological studies have shown correlations between particulate pollution levels and excess morbidity and mortality. I believe that the methodology was decent and the obvious controls (smoking, obesity, etc) were done. http://www.nrdc.org/air/pollution/qbreath.asp
The NRDC estimates on the basis of this work that there are 64,000 excess cardiopulmonary deaths annualy in the US attributable to particulate pollution.

Anon E. Mouse writes:
George. Light duty diesels are not causing those deaths. Trucks/buses/construction equipment are causing those deaths.

I'm open to the argument that light duty diesels are a minor contributor to the overall human exposure to particulates, though I'd want to see some data. I do know that when I am driving behind a light duty diesel, my personal exposure to particulates is WAY higher than I want it to be.

CO2 is, yes IS, causing hundreds of thousands of deaths per year already.

CO2 is causing hundreds of thousands of deaths? Are you counting hurricanes and typhoons? Where does this come from?

The planet is roasting and you're oblivious.

My wife might agree with you on the latter. I am not a GW denialist. I think there are lots of good ways to reduce GH gasses without increasing toxic pollutants.

Carl writes: Particulate matter (PM) from on-road diesel engines (including heavy-duty) really is a non-issue starting in 2007. The U.S. regs will effectively mandate use of PM filters which are clearly very effective. Studies have shown that PM from light-duty diesel vehicles are less than PM from low-emitting gasoline vehicles in terms of both mass and number. Even diesel-hating CARB has acknowledged this.

If this is true, then I will definitely reevaluate my opinion of diesels. At the moment, "clean diesels" remain vaporware, but there are an awful lot of dirty ones on the road.

George Writes: I do know that when I am driving behind a light duty diesel, my personal exposure to particulates is WAY higher than I want it to be.

Then I have a question for you:

1. Which would you rather be behind the LEAST?
a. Gasoline compact car circa 1996
b. VW TDI circa 2006
c. VW diesel compact circa 1996 burning B100

Anon -

that's easy: 1c will produce the highest PM emissions and smell like burnt french fries. Biodiesel reduces PM by ~30% but those old engines featured rather dirty combustion of whatever fuel they were fed. Diesels have advanced more in the last decade or so than they did in the preceding century.

The modern TDi will be better mostly because of higher injection pressures, but also because the vehicle features a larger power/weight ratio. That means the engine doesn't have to max out the engine load to get decent acceleration, reducing the smoke puff characteristic of load step changes in diesels without PDF.

Gasoline cars featuring homogenous charge combustion and three-way catalysts produce virtually undetectable emissions of CO, HC and NOx once the cat reaches light-off temperature. PM was an issue with first-gen (wall-guided) stratified GDI, but this has now been eliminated via spray-guided GDI featuring piezo injectors and CR pressures of 150 bar (e.g. Mercedes M272DI engine). European manufacturers have really benefited from technology cross-pollination between gasoline and diesel engine development.

Pizmo wrires: Bins 2 through 6 allow a maximum of 10 mg/mile. This person isn't even getting his decimals in the right place. What he meant to say is that the PSA cars (per his claim) are getting 5 mg/mile (or as its put in normal lingo, 0.005 g/mile) compared to the maximum .01 g/mile for most current gasoline vehicles, not the "advanced gasoline cars".

Actually, the 0.5 mg/mile PM for DPF-equipped light-duty diesels matches quite well with other sources, so I don’t think it’s a misprint or decimal error. A European (Swedish) study shows a 0.3 mg/km which would equate to approximately 0.5 mg/mile (although it used a different drive cycle, NEDC vs. FTP75 – see slide 63 of http://www.vagverket.se/filer/publikationer/2002_62.pdf ). Also, EPA measured 1 mg/mile city and 0.4 mg/mile highway with their CDC light-duty diesel (see slide 11 of http://www.epa.gov/otaq/technology/deerpresentation.pdf ).

As far as NOx is concerned, I agree that it’s still an issue with diesels. However, as you can see with the last EPA link I provided, EPA’s CDC program is looking promising for reducing engine-out NOx levels to Bin 5. I think Mike posted an article recently that Ricardo expects to be able to meet Bin 2 with a combination of technology like CDC and after-treatment.

George writes: I'm open to the argument that light duty diesels are a minor contributor to the overall human exposure to particulates, though I'd want to see some data.

George, I’m an air pollution meteorologist and I often have the opportunity to attend clean air conferences. I attended one in May of this year in Oak Ridge, TN. One of the presentations was a study to quantify diesel particulate matter (DPM) in large southeastern U.S. cities (one of which was Atlanta). Even in these urban centers, ambient DPM levels were estimated to be 1 microgram/cubic meter or less (which is about 3% or less of the total fine particulate concentrations), and that includes DPM from ALL diesel sources, large on-road trucks, off-road construction equipment, etc. Sorry, I don't have a link to this study.

I’ll also agree that older diesels are high emitters. However, these new clean diesels appear capable of near-zero emissions of all pollutants, regulated and non-regulated. I’m a diesel proponent because I think they can be an environmental benefit in terms of both CO2 emissions and clean air.

As far as NOx is concerned, I agree that it’s still an issue with diesels. However, as you can see with the last EPA link I provided, EPA’s CDC program is looking promising for reducing engine-out NOx levels to Bin 5. I think Mike posted an article recently that Ricardo expects to be able to meet Bin 2 with a combination of technology like CDC and after-treatment.

Yet what happens to the PM levels? The point is that (and was) that the problem has been getting all the criteria pollutants down to the Tier 2 threshholds, and apparently the manufacturers were unable to achieve that as of this model year.

However, these new clean diesels appear capable of near-zero emissions of all pollutants

Where are they? They're still in the lab.

The picture for diesel is going to change for me when the vehicles are on the road, demonstrating emissions and fuel economy performance, and also demonstrating their economics. We have gasoline vehicles now that are very fuel efficient and operate at the very high end of the emissions standards, all for a few extra thousand dollars upfront. When diesels can match all that, then they're going to be a net positive from an environmental perspective. If changes in the fuel availability bring more biodiesel into the mix as well (the right kinds, of course), then that will be a winning technology.

It seems to me that some criticism of diesel-electric hybrids is focused on "full hybrids". Why not make "mild hybrid" diesels that simple use a starter-alternator and shut off at stoplights? That would seem to provide significant benefit with little weight or complexity penalty.

Yet what happens to the PM levels?

Nothing. What are you referring to? Both NOx and PM are below Bin 5 levels (PM well below). Only HC gets above Bin 5 and according to the text below the graphic in the EPA link, “this test configuration did not have an oxidation catalyst to help clean up the HC & CO down to the “bin 5” levels.” (although CO is still way below the rather lenient CO levels of Bin 5).

By the way, MB E320 BlueTec meets Tier 2, so there’s one anyway.

The picture for diesel is going to change for me when the vehicles are on the road, demonstrating emissions and fuel economy performance, and also demonstrating their economics. We have gasoline vehicles now that are very fuel efficient and operate at the very high end of the emissions standards, all for a few extra thousand dollars upfront. When diesels can match all that, then they're going to be a net positive from an environmental perspective. If changes in the fuel availability bring more biodiesel into the mix as well (the right kinds, of course), then that will be a winning technology.

Fair enough, but one issue that needs to be considered with gasoline vehicles is the evaporative emissions (VOCs) associated with handling their very volatile fuel (gasoline or even ethanol). Even gasoline vehicles that are classified as PZEV are still responsible for a lot of VOCs in the production, distribution and refueling of the gasoline. Diesel/biodiesel fuel is essentially non-volatile, so this is not an issue with diesel vehicles.

Gasoline vapors decompose in the atmosphere to formaldehyde (a carcinogen) and secondary organic aerosols (i.e., fine PM). A large fraction of ambient PM2.5 is often organic carbon (generally much higher fraction that EC). Do we know how much gasoline vapors are contributing to the organic carbon fraction of the PM2.5 inventory?

Zack,
There is another way to have micro-hybrid instant startup from stop capbility.

http://www.all4engineers.com/index.php;site=a4e/lng=en/do=show/alloc=3/id=5139

Rafael Seidl pointed this out in gas/spark ignition engines, and I think it may be usabel in compression ignition engines. The one problem with using direct start in diesels is ingition temp required to operate compression ignition engines. Perhaps the good old spark/glow plugs will find a new role as startup assists.

Nothing

Well, no, first you started by mentioning a technology with ultra-low PM emissions, then segued into talking about a whole other (lab-based) technology. The point (which I keep needing to make to you for some reason) is that you squeeze one end of the metaphorical balloon and it expands somewhere else. The ultra-low PM emissions in Peugeot were balanced out with much higher NOx. The EPA's test engine had higher PM numbers than the Peugeot -- much much higher.

By the way, MB E320 BlueTec meets Tier 2, so there’s one anyway.

Wow. One. What's the sales for it relative to the whole light vehicle market? It's also not even 50 state, is it? Again, it's not relevant until diesel starts getting into mass market price points with ultra low emissions. It's going to be at least several years before we start seeing that, probably beginning with Honda's offering.

Fair enough, but one issue that needs to be considered with gasoline vehicles is the evaporative emissions (VOCs) associated with handling their very volatile fuel (gasoline or even ethanol). Even gasoline vehicles that are classified as PZEV are still responsible for a lot of VOCs in the production, distribution and refueling of the gasoline.

That's easily regulated, since it's a supply-side issue.

Do we know how much gasoline vapors are contributing to the organic carbon fraction of the PM2.5 inventory?

No, but I'm betting that Diesel Fuel News or some similar "objective" source will let us all know all about it. ;)

Well, that's funny. It's easy to say the advantage of diesel cars when you are not living in a country full of diesel.
VW and Mercedes are the worst diesels from PM viewpoint. BMW, Renault, Fiat, PSA, Toyota and Honda build way better diesels; I see many TDI and CDI with black smoke on tailpipe and almost none of D4D, HDI, CDTI, dCI.
Another point: do you want to wake up all your neighbours when you start your precious TDI in the morning? Yes, it's reliable and it has the best mpg, but at what cost?
E320 Bluetec... let's see in real world. Wait for recalls, for clogged filters, for cars stopped in cold winters (of course, it was the bad fuel, but prove it!).
If Europe had better regulations for PM/NOx, situation would be better today for everybody, including diesel manufacturers.

The advantage of the diesel engine is not so much the improved mpgs, but where the fuel can come from. SI engines are just too limited.

My TDI only idles noisily for a few seconds on a cold morning.  Lots of people's cars crank louder than mine fires up.

I think people overlook the fact that today's gas engines are tuned for more power vs fuel economy. My father had a 1988 Camry with a 2.0 four that consistently obtained 31 m.p.g. at 80 mph even with the air conditioning on economy mode. The new Camry can get no better. What twenty years of technology has given everybody is more power but not fuel economy. If all automakers tuned down their cars/trucks the fuel economy would grow substantially without the need for diesels or heavyweight and overly complex hybrid systems.

Think of the hybrids in another way. Because of the added weight your tires/brakes/suspension components will not last as long. I think Toyota wanted around $1,500 for new struts and tires can easily cost you $500. Handling and braking are also poorer in a hybrid so I would certainly think that there are other variables to consider when comparing hybrid to nonhybrids.

Given the claim that producing a car consumes more energy than the car will consume in the car's (average) lifetime, and given the claim that allowing for energy consumed to ship material to Japan to produce a hybrid, production of a Toyota hybrid generates more CO2 pollution that building a Land Rover in the UK, the CO2 reduction during the life cycle of a hybrid, vs a non-hybrid version of the same vehicle, is questionable. Until I see facts to the prove me wrong, I think only if solar energy is used to produce produce a hybrid car and/or solar power used to charge the batteries of a electric cars, will these vehicles reduce CO2 air pollution.

So, from my point of view, the smaller the vehicle, the lighter the vehicle, the more aerodynamic the vehicle, the less CO2 released during the production, operation and recycling of the vehicle. The best vehicle for my all weather weekly needs is a Toyota Yaris. Plus I think the Toyota Yaris has a better designed dash that other eco-friendly vehicles. Only with the Yaris, can I mount my aftermarket navigation behind the steering wheel, where it is easy to see. Important for a disabled person, like myself, is availability of items like automatics and A/C. Which Yaris offers, and (in the US) many imported economy cars do not offer a automatic transmission.