Volkswagen diesel car wins "Green Car of the Year"

The improved emissions profile I think, that allows this car to be be sold in the US.

My cynical side also whispers that the auto show has to give the award to *somebody*. This car was just the best of a pretty uneventful year on the green front. Btw, notice the 41 mpg is the highway mpg only ? Guess 30 mpg city ! just doesn't ring quite as nice.

 

A fav SAT question. 150 is 50% more than 100, while one hundred is 67% of 150

The Europeans do it right: pollutant/distance. Whether it be NOx or CO2 or whatever.

 

You have to consider he source. Last year "Green Car Journal" chose the Chevy Tahoe hybrid as the 'green car of the year.' Their standards are not what you might assume.

 

Soon there will be even more Diesels on the road. GM, Ford, And Dodge are all releasing Diesel motors in there half ton trucks. Effin sweetness!

 

<shrug>I'm not sure what diesel gives to most trucks other than torque -- and that can be solved by gearing.

 

I have wondered the same thing. I think what it "gives" to a truck (speaking specifically of a pickup truck, not big rigs) in the eyes of most purchasers or prospective purchasers is a certain macho cachet, the sound and smell and 'persona' of a diesel. There is increased efficiency to a certain extent which made them economical when the price of diesel fuel was closer to that of gasoline, but definitely not enough to make them economical in today's environment.

:behindsofa:

 

Clett,

Where did you get those numbers from??? The part about more specific energy per volume is correct, but the efficiency numbers are all wrong. It would be absolutely fantastic for any ICE to get even close to 30% of efficiency, let alone 43% or 50%, that is complete rubish!

The Prius only succeeds in going above the 20% threshold thanks to its electric motors, or it would also be quite bellow the 20% mark. There is no engine on the face of the earth that can give you the efficiency numbers you state.

And, above all, like others have already stated, please see emission figures for ANY diesel car and compare them to the Prius. I too live in Europe, so I know what I'm talking about. Here in Portugal over 50% of cars are diesel, and we pay dearly for it. I find it disturbing to find so many Americans are looking forward to diesel... they don't have a clue of what's coming if they go that way...

Pick your best diesel, be it Blutech, or Blumotion, or whatever. Go to "vca car fuel data org uk" and search it. Now search the Prius and compare them. Now do a search on the health effects for all those emission types on the internet. It's quite scary isn't?

Cheers,
João Prates
prius-pt.com

 

Well, there are, but they are exotically expensive and special purpose engines. I'm talking about "prime mover" engines from Wartsila and Waukesha. With per-cylinder fuel and spark control and advanced valve timing profiles, they can meet 40% efficiency

These engines are typically used as peak power electrical generation, natural gas pumping, oilfield pumping/power, large facility power generation, etc. They cost millions of dollars, weigh over 100 tonnes, and are rarely seen by the average citizen

When used with co-generation, the efficiency can approach 80-90%. I strongly encourage clients to consider cogen, there are enormous cost savings for future operations

 

They are reasonably close to published figures:

Toyota claims a peak thermal efficiency of 38.5% for the Prius, partly due to its use of the Atkinson/Miller cycle. I have seen claims for the VW diesels of about 46%. The very large container ship diesel engine that was mentioned in another thread recently had a peak efficiency of about 50%.

Now these are under optimum conditions, so yes the average will be significantly less, one of the features of the hybrid system as used in the Prius is to maximize the system efficiency by attempting to keep the engine in the optimum operating region and use the battery to average the load and to propel the car when only low power is required where the ICE would be inefficient.

kevin

 

I think the simplest way to see that Clett's efficiency numbers are over optimistic is to look at the CO2/km data available on all European cars. Prius is about 100 grams/km (or is it mile ? -- not sure). Good luck finding a diesel car about Prius size and weight that emits 70 - 80 grams/same distance.

This nice site has CO2/km data. A couple of diesel models emit about 5% less CO2 than Prius, but to my knowledge they are all much smaller and lighter cars, and their non-CO2 pollution profiles are between bad and awful.

 

I haven't seen a source for efficiency testing of a small vehicle diesel like the VW, I'd be very interested to see some real data.

For the Prius, there is the study done by the Argonne National Lab. They inserted a torque sensor between the ICE and the rest of the drive train, to characterize the engine performance in situ. They found that the Prius engine stayed between 35-40% efficiency over a very broad range of power delivery. So not only does the Prius engine have very good peak efficiency, but more importantly it is possible to achieve numbers near that peak efficiency over a wide variety of conditions. For example they found that steady state cruising at 50mph yielded an efficiency of 34-37%, while cruising at 60 yielded 37-38%. My understanding is that this is thermodynamic efficiency of the ICE itself, because the torque output is measured before the PSD. For the steady state cruising cases, the electric system should be largely irrelevant anyway.

http://www.transportation.anl.gov/pdfs/HV/454.pdf

Rob

 

Haven't found any real good data, but here is one source of testing data done on the 1.9L TDI for someones thesis. They were able to get a similar 35-39% kind of efficiency over a range of 10-60hp. This is bench testing though, not in car.

http://www.ohiolink.edu/etd/send-pdf.cgi/Van Horn Charles.pdf?acc_num=akron1154354134

Rob

 

...yes, agree, of course if we mention only PEAK values... but not even our beloved Prius works at optimum efficiency all the time... and we do have the precious help from the MGs, something no diesel has.

The most important point to me is that diesel is by far the worst poluting fuel. Here on Europe they try to pass the silly idea that only CO2 matters, nobody else mentions the HC, NOx and the rest.

German car makers don't even offer particle filter as standard on all their models! What kind of "green" cars do they do after all???

 

On the contrary miscrms.

I don't have the link with me now, but the main losses on the Prius (and on any trany for that matter) are located on the transmission part. It's the last stage after the PSD, the reduction gears, that loose the biggest chunk of efficiency.

The efficiency of the ICE can be high, but we need to address the GLOBAL efficiency for the vehicle, not the ICE alone. That's why the Prius beats any diesel easily. The higher efficiency of the electric motors overcompensates the losses at the gears.

This is how I read it.

 

I agree.
Especially, the PM2.5 or smaller particles can't be filtered using current DPF technology.

The health effect is still unknown, but it'll be found soon.
Diesel - Wikipedia, the free encyclopedia

Ken@Japan

 

I guess it is time to repost this again.

I also challenge all my fellow Prius owners here to prove that the Prius has no particulate emissions. Go outside and wipe your finger inside the exhaust pipe (once cooled of course ) I'm sure it won't have any soot on it. (Also know as particulates) Just because the US and EU regulations don't check for particulates doesn't mean that the Prius doesn't produce them.

Consider VW’s newest diesel engine the TDI CR (Turbo-charged, direct-injection, common rail) vs their newest gasoline engine the TSI “twincharger” (Turbo-charged, supercharged, direct-injection)

This is data from the UK equivalent of the EPA found here: VCAcarfueldata.org.uk
The performance data is from Volkswagen UK.

Vehicle -------------------------Golf----------Golf-----------Golf---------Golf----------Passat---------Passat
Performance:
Engine ------------------------1.4L TSI --- 2.0L TDI ----- 1.4L TSI ------ 2.0L TDI ----- 2.0L TSI ------ 2.0L TDI
Power (PS) ----------------------140----------140 ----------170 ----------- 170 --------- 200 ---------- 170
Torque (Nm) -------------------- 220 -------- 320 --------- 240 ----------- 350 ---------- 280 ---------- 350
Interior Noise (dB. ) ------------- 73 ---------- 72 ---------- 74 ------------- 73 ---------- 73 ------------ 69
0-60 mph (s) ------------------- 8.8 --------- 9.3 --------- 7.9 ------------ 8.2 ---------- 7.6 ----------- 8.6
Fuel Economy (l/100km) -------- 7.1----------- 5.5 ---------- 7.3 ----------- 5.9 ---------- 8.1 ---------- 6.1
Emissions:
CO2 (g/km) -------------------- 169 --------- 145 --------- 174 ----------- 156 --------- 193 ---------- 159
CO (g/km) --------------------- 0.343 ------- 0.103 ------- 0.283 -------- 0.033 ------- 0.512 -------- 0.093
HC + NOx (g/km) -------------- 0.085 ------- 0.261 ------- 0.074 -------- 0.222 ------- 0.064 -------- 0.177
Particulates ------------------- 0.042 -------- 0.000 ------ 0.034 -------- 0.000 ------- 0.053 -------- 0.000

Total Emissions (less CO2) --- 0.470 -------- 0.364 ------- 0.391 -------- 0.255 ------ 0.629 -------- 0.270

Note: The UK TDI engines have the Particulate Filters but not the NOx Catalyst used in the US version. The US version with the NOx Catalyst produces 0.05 g/mile or 0.0805 g/km of NOx. This is a 66% reduction from the UK version though the test cycle is slightly different.

Notice that the diesel engines are quieter, get better fuel economy, and have lower emissions than their gasoline equivalents. The gasoline versions accelerate faster 0-60 due to higher redlines that allow for fewer shifts. I would expect that the diesel would accelerate faster 50-70 in top gear due to the much higher torque output.

Hybrids such as the Prius have lower emissions than any of these engines but that is due to the hybrid system not the superiority of gasoline engines over diesel engines. I expect that a diesel hybrid would have similar reductions in emission as a gasoline hybrid.

 

jhinton said

I'm pretty sure the opposite is true. The Prius emits more in the city in stop&go ICE use than on the highway. So *despite* the Prius being a hybrid, it has a superior emissions profile.

 

Have a look at this graph from Oak Ridge National Labs in the US. The vertical axis is watts:

 

I dont agree

a diesel got more energy per liter off fuel
so you have more power

and your comparing a commen rail diesel to normal gas ice cars?
Look at what you all need to make that diesel cleaner? filters all over the place and dont forget these deisels have variable turbo's etc

lets compared that to a real modern lean burn petrol car like a TSI also from VW.

also when you put a diesel inside a hybrid it will not perform that well because a diesel uses heat and compression to burn fuel
when the ICE from a diesel shuts down like with a hybrid its cools down like with a petrol car
but when you start it again it needs to get warm again to burn fuel effecient again unlike the petrol car that get hotter faster if i am correct!

then your diesels are more expensif with all the filters that wil make the premium price for a hybrid a lot more then with petrol cars.

 

What do you mean??? The very same site I mentioned earlier and you are using now clearly states the Prius has no MEASURABLE particle emissions, as most gasoline cars don't. What's the news? I have measured the particulate emissions myself on an inspection center here in Portugal, it gave ZERO particulate emissions as well. What do you prefer? To have a car that has particulate emissions that can be easily measured or one car that has them so low you can't measure them?

Why on earth should we? I could not care less about the VW inneficiency and dumbness. So they can't produce clean cars, so what? We need to compare their best TDI with our Prius, that's the right comparison. I believe you don't know it, but this is their most "clean car ever", the high-tech display of all of VW clean tech: the Bluemotion Golf... VCAcarfueldata.org.uk - Search Results - Further Information

This Golf as 110 ps just like the Prius... now have a look on the emissions record of this Bluemotion miracle...

CO2: Bluemotion = 119 g/km : Prius = 104 g/km
CO: Bluemotion = 391 g/km : Prius = g/km
HC: Prius = 0.02 g/km
NOx: Bluemotion = 116 g/km : Prius = 0.01 g/km
HC + NOx: Bluemotion = 186 g/km
Particulate: Bluemotion = 0.7 g/km : Prius = 0 g/km

Put it another way, using the Prius as reference 100%:

CO2: Bluemotion = +14,4%
CO: Bluemotion = +217%
HC + NOx summed up: Bluemotion = +6200%
Particulate: Bluemotion = infinite

So, you got to be kidding defending the diesel, right?