Volkswagen diesel car wins "Green Car of the Year"

jprates, I've clipped out a table from Toyota's Life Cycle Assesment pdf you may find surprising; I know I did. Look at the PM.

 

Here you go. You won't find a single gasoline vehicle that has PM data listed.

Annual Certification Test Results & Data | Cars and Light Trucks | US EPA


In the US there are no longer diesel / gasoline requirements. As of 2007 all vehicles must meet the same requirements. However, gasoline vehicles have no data reported for PM and diesel vehicles has no data reported for EVAP testing. It is weird but I'm sure the exception is listed in the hundreds of pages of regulation also available for your viewing.

 

SageBrush you're misinterpreting the data.

That is, as you quote, data from the complete LCA, it is not from vehicle's active life while you are driving it.

Look how small the PM during the "Driving" phase there is. The big chunks are on "Material production" and "Vehicle production". And I bet my money that those PM values came from diesel engines used on heavy duty machinery during these phases.

Anyway, I never said there is no PM emissions on the Prius, I said they are too small to be measured.

And again, for the nth time, I don't want to keep on discussing PM. What's wrong with all of you guys? Here in Europe all they see is CO2 emissions, and it seems for you fellow Americans all you see is PM. Why on earth can't we have a global vision on the vehicle emissions problem? Please see the big picture.

 

Finding actual PM measurements is indeed a chore, but here is some data from a research article http://www.google.com/url?sa=t&source=web&ct=res&cd=14&url=http%3A%2F%2Fwww.cse.polyu.edu.hk%2F~activi%2FBAQ2002%2FBAQ2002_files%2FProceedings%2FSubworkshop6%2Fsw6a-3Jacobson_Final.pdf&ei=MGQsSYXREpm0sQPxvMTlAQ&usg=AFQjCNF4Rc7CgD0nNmuHOdBPUSjZVpVuGg&sig2=3dfRh-uR48mL0KZGsOZHZw

Snippet below

 

Between the three of us, you are preaching to the choir regarding Prius. But accuracy has it's own rewards. And, we like to argue.

I didn't comment on the LCA graphic so I am surprised you can read my mind ;-)
The graphic did make me wonder whether the PM emissions of a diesel during a lifetime of driving are greater than the larger amount produced in Prius production, even estimating PM of Prius driving at zero. I don't know the answer, which in and of itself surprises me. I also don't know if the emissions are comparable in how they effect air quality.

 

See this is what I don't understand, you seem to have a fanatical hatred of diesel vehicles but not gasoline vehicles. If you hate pollution and all vehicles that pollute you should hate every vehicle except hybrids and EV's.

Earlier I posted some information comparing gasoline engines to diesel engines in VW's. You disregarded this as poor engineer on VW's part and said I should look to Toyota. Here is Toyota's info (all in g/km)

Petrol Cars:
Car---------- Yaris ------- Auris -------- Avensis --------- Verso
Engine ------ 1.3L -------- 1.6L ---------- 1.6L ------------- 1.8L
CO2 --------- 136 -------- 164 ----------- 187 -------------- 179
CO --------- 0.490 ------- 0.811 -------- 0.450 ------------ 0.410
HC+NOx --- 0.060 ------- 0.059 -------- 0.070 ------------ 0.070
PM----------- N/A --------- N/A ---------- N/A -------------- N/A

Diesel Cars:
Car---------- Yaris ------- Auris -------- Avensis --------- Verso
Engine ------ 1.4L -------- 1.4L --------- 2.0L ------------- 2.2L
CO2 --------- 119 -------- 129 ---------- 149 -------------- 164
CO --------- 0.070 ------- 0.094 ------- 0.170 ------------- 0.100
HC+NOx --- 0.180 ------- 0.192 ------- 0.220 ------------ 0.230
PM ---------- 0.018 ------ 0.023 -------- 0.019 ----------- 0.020

Should a buyer choose the petrol or diesel version?

From the UK website and Toyota UK it seems that Toyota has no plans to offer particulate filters on their diesel vehicles until required to by Euro V. This is not very green of them.

Yes, Toyota offers the Prius and its green halo shines down on Toyota. However if you look at the rest of Toyota's model range you'll find it is business as usual.

BTW, when you compared the VW Golf Bluemotion to the Prius you got the figures wrong. The site lists emissions for the Prius in g/km and for the VW in mg/km (milligrams per km) You are off by three decimal places. Yes, the Prius is still cleaner but not 2000x cleaner.

 

I too love to argue, as long as the argumentation makes sense and you are indeed being accurate. I find this discussion hardly deserves that title. You are missing all other gas emissions and only care about PM. How can this be called "accuracy"?

Again, being accurate, I have to say you did comment the graph. You said, and I quote "you may find surprising; I know I did. Look at the PM."

Of course you do know. It's easy. The difference between producing a diesel car and a gasoline car is very small. One can argue that it uses about the same energy and the same environment impact. Although of course it seems that from an engineering point of view it seems harder to build diesel, or so do manufacturers say... don't know why...

So all you have to do is to assume the gasoline car is equivalent to a diesel, and then sum up all the pollution a diesel car makes in its life. It's frightening. Consider that 80% of all pollution is made during a car's usable life. Now multiply the Prius pollution by dozens of times for some gases and thousands of times for others. See the dark picture?

That is plain easy SageBrush, and you know it just Google, you'll find a lot about it. We have several ph doctors and biochemistry graduates on our forum here in Portugal, and we had a discussion on this a few weeks back. One of the doctors came up with so many documented studies about cancer effects caused by diesel emissions that we had to ask him to stop getting more, it was quite impressive.

 

Interesting. I wonder what size PM they were measuring. I'm also not very impressed with their methodology. For the Diesel PM they took data from one vehicle. For the gasoline PM data they took "The average of the 12 lowest emitting passenger vehicles and light-trucks". A bit apples and bananas, I expect more from Stanford. Still its something.

Regarding you comment of PM from manufacturing and driving for the Prius. At least according to this EEA report, only 15% to 22% of all PM is from vehicles:

http://dataservice.eea.europa.eu/ge...download\CSI_003_AssessmentV1_Figure3\png.png

 

I read (somewhere) while browsing today that the PM filters will cost about $500. No wonder the manufacturers are slow to put them on. Anyway, to summarize my opinions about diesels and then leave this thread: I'm happy to have them compete in the marketplace IF they meet the same pollution controls as gassers, and have level taxes applied.

 

jprates, my comment about emissions and relative air effects was regarding PM from vehicles during driving vs PM from manufacturing. I do read the medical literature regarding diesel affects on health -- I am an MD, and I have personal interests in public health as well as asthma.

Don't be so quick to jump to conclusions.

 

I hope the Priuschat community will allow a Jetta TDI owner to join this lively discussion.

I am an atmospheric scientist and have been involved in air quality/air pollution for nearly 25 years (currently in air quality forecasting). I have more than a passing interest in emissions and their effect on air quality. I have had discussions with at least a few of the members here (Rob (miscrms) and jhinton) on the TDIClub site.

As far as PM emissions are concerned, the Prius may have PM mass emissions below detection limits, but so does the '09 LEV II Jetta TDI (CARB certified @ 0.000 g/mi), as jhinton mentioned. Also keep in mind that the test cycle in which these emissions are measured is an unrealistically gentle cycle (both the FTP75 and the NEDC). Gasoline engines have been shown to have PM emissions (particle number) that increase exponentially with increasing load (Kittleson, et al, Nanoparticle emissions on Minnesota highways. Atmospheric Environment, Volume 38, Issue 1, January 2004, Pages 9-19). So under high speed/rapid acceleration conditions, gas engines can have PM number emissions similar to that of unfiltered diesel engines (load does not have as much effect on diesel PM number emissions). Cold ambient temperatures also dramatically increase gas engines' PM emissions. EPA recently acknowledged that they have been underestimating gasoline PM mass emissions by 60% (i.e., a factor of 1.6) based on a study they commissioned in Kansas City. Diesel particulate filters (DPF) have been shown to be very effective across the entire particle size range, and in some cases the number of particles in the exhaust of a DPF-equipped diesel engine has been shown to be less than the filtered air in the dilution tunnel, i.e., the engine is serving as an air cleaner.

One more point, "tailpipe" emissions don't fully account for all emissions for which a vehicle is responsible. Evaporative hydrocarbon emissions are also important. Ambient levels of HC determine the ambient concentration of ozone, NOT NOx (ozone is the primary constituent of "smog"). In addition to being the main "smog-forming" emission, HC oxidizes in the atmosphere to formaldehyde (a carcinogen) and eventually particles (secondary organic aerosols - SOA), especially longer-chain/aromatic HC. SOA is mainly in the nasty ultrafine particle size category. The Prius' certified HC emissions are almost twice as high as the TDI's if you include the evaporative emissions from the vehicle (diesel fuel obviously is essentially non-volatile). Evaporative emissions are also the main source of "MSATs" (mobile source air toxics - e.g., benzene)

As previously mentioned, the CARB-certified PM mass emissions of the LEV II Jetta TDI are 0.000 g/mi. The significant figures imply the PM mass emissions are <0.0005 g/mi. The SOA produced by the Prius' vehicular evaporative emissions would approach that emission rate (average SOA yield ~4%), even if you assume ZERO direct PM emissions from the Prius. And this doesn't even take into account the evaporative emissions from the distribution and storage of gasoline at gas stations.

I want to make it clear that I'm not bashing the Prius or any other hybrid (it's great technology in my opinion), just defending the "clean diesels" on scientific grounds. Certainly, the Prius is exceptionally "clean", but so are the T2B5 "clean diesels".

 

And that's precisely what I do. I never said I loved gasoline vehicles.
Can you please point me one place where I said that?
And one more thing, I do not have "fanatical hatred", I have "scientifically supported hatred" at most. Don't try to pull this into the irrational side.

Again, I never said that, please read my posts as I wrote them, not as you interpreted them.

Indeed I am 100% with you on this one (finally): I don't care if it is Toyota or VW, as long as it is pollutant I simply hate it. Toyota builds too much Land Crushers if you ask me. They like to build the Prius to show as a flagship, but have a lot to do on their upper models, specially the diesel ones.

Thanks for pointing that one out! I had never noticed this before.
Anyway, like you said, the Prius still beats the hell out of the Bluemotion

 

I surely hope not, I loved your post, thanks for sharing this insight info.

PM PM PM PM... I'm getting tired of this... I'm not the one coming back to PM all the time... oh boy...

Anyway, if you read the PM values for most DPF fitted cars you will find out that most do not filter all PM at all. Look at Opel ones (GM brand), and be shocked. It is a new trend now on Europe: they say they have DPF and then you discover they still emit PM...

On a second question, specially for you who might know the answer: what happens to all that PM that gets caught on the DPF? Some work by heating the internal chamber so hot it "burns" all the accumulated PM there. Nice... but... wait... it gets burned... that means it gets smaller and gets expelled the same way into the air??? What actually happens there? Nothing gets lost in nature, everything is transformed, so where did all that PM get??? My gess is that it is burned and expeled...

Some other type of DPF work by putting some kind of liquid into it, don't know exactly how or where, but some like Peugeot and Ford require this liquid every x.xxx miles or else the DPF will get broken. What is this liquid for? What happens to PM in the DPF? The liquid by the way is outrageously expensive!

Of course the 3rd type is even more expensive requires you to take the DPF out and put a new one every xx.xxx miles. How nice.

Now that's nice, too bad there are a lot of other emissions coming out as well anyway... heavy metals like NOx, As, Se, Cd, Zn, SOx, several poly cyclic hydrocarbons, etc. Do you see the same amount of these emissions on the Prius? I don't think so, not even a fraction of them, and most are absent, simply because they only exist on diesel on significant proportions. Am I wrong?

I'm terribly sorry, no pun intended, but I REALLY REALLY do NOT believe this part. Do you have proof of what you wrote? There is no way I will believe the evaporative emisions from the Prius or any other car for that matter will overdo the diesel emissions from a tailpipe... no way!

 

Sorry all, but I just found an easy proof to show how wrong this statement is:

The Prius is as we all know an AT-PZEV vehicle. One of the things a car must have to be classified as AT-PZEV is, and I quote:

"A car with AT-PZEV certification, such as the Toyota Prius Generation III Hybrid, has near-zero tailpipe emissions and zero evaporative emissions. It is one step cleaner than the generation II Prius' Super Ultra Low Emission Vehicle (SULEV) certification."

So, there you go, the Prius has no evaporative emissions at all, wxman your line of thought goes astray. :rockon:

You need to study the Prius a bit more I would say

 

Thanks for posting, wxman.

Do you know if PM below a certain size escapes detection by methods currently used by the regulatory agencies ? I'm also curious if current DFPs degrade over a vehicle's lifetime of use. Color me skeptical, but I expect to find that the filters that will become widespread in use with Euro V will just manage compliance of 5 mg/km. Money talks.

Do chime in -- what is your guess for an average PM emission for T2B5 gassers ?

 

Actually, I included several links in my original post, but I got a message that links weren't allowed until I have at least 5 posts.

The MSAT data are from USEPA data.

The Prius is certified in California as AT-PZEV, but the evaporative emissions aren't *really* zero, just below a "diminimus" level that CARB considers zero.

Based on the CARB cert sheet for the AT-PZEV Prius, the certified emissions data are 0.01 g/mi running loss (0.05 g/mi max) and 0.16 g/test 3-day diurnal (0.35 g/test max). These together exceed the certified "tailpipe" NMOG emissions of 0.009 g/mile. According to CARB, the 3-day diurnal emissions can be converted to g/mi by dividing the value by 50 (0.16/50 = 0.0032 g/mi). 0.009 + 0.01 + 0.003 = 0.022 g/mi which is greater than the CARB certified emissions for the LEV II Jetta TDI (0.012 g/mi). 0.022 g/mi - 0.012 g/mi = 0.010 g/mi x 0.04 (4% average SOA yield for HC emissions) = 0.0004 g/mi (0.4 mg/mi).

Since I can't include links in my posts yet, you need to go to the CARB cert web page that jhinton referenced earlier for verification.

 

There are lots of different types of particulate filters and each works differently. However they all take carbon (C) and burn it to create other compounds. Some of these compounds are CO2 and H2O. This company has some good details on their page.

Technologies - Diesel Particulate Filters - Regeneration

 

Yeahh, if we get even a *whiff* of diesel, we filter.

Kidding

 

SageBrush - according to Fujita ( Fujita, et al, “Variations in Speciated Emissions from Spark-Ignition and Compression-Ignition Motor Vehicles in California’s South Coast Air Basinâ€. Journal of the Air and Waste Management Association, June 2007) the "average" PM emissions from SI vehicles was 27.2 mg/mi (0.0272 g/mi) for cold start tests and 16.9 mg/mi for hot start tests. They measured a max of over 250 mg/mi, although this obviously was a high emitter.

For PM sizes, the current methods are limited to somewhere around 5 nm aerodynamic diameter. According to several studies I've seen (e.g., Storey et al., ORNL, "Comparison of Direct Exposure of Human Lung Cells to Modern Engine Exhaust Particles." Proceedings of the 2003 DEER Conference) DPF-equipped Mercedes diesel had less particles (numerically) than the ambient air, right down to the <10 nm sizes.

 

As far as a estimate of T2B5 gassers' PM emissions, a test conducted by the "Association of Emission Control by Catalyst" (a European outfit, I believe), new U.S. cars emitted an average of 0.4 mg/km.

The same study indicated diesels with DPF emitted an average of 0.3 mg/km. This study also suggested that CO from DPF diesels was one-tenth the average of the new gassers and had less than half the HC emissions. Non-DPF diesels averaged 23 mg/km PM.