- #7219 of 8144
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Re: Porsche Diesel [houdini1]
by jlbl
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Nov 25, 2008 (11:20 am)
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Replying to: houdini1 (Nov 24, 2008 7:10 pm)
Hey Dan, nice to hear from you.
I'm doing reasonably well, given the circumstances.
My 335d coupe is a joy now that her engine is easing after 12500 miles. The only thing I miss is manually shifting—though I use to drive her in M mode most of the time. I'm really satisfied with this car. 530d was more fuel efficient, but 335d is more a driver's machine.
Thanks for asking,
Regards,
Jose
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- #7220 of 8144
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From the NYT today..
by kdhspyder
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Nov 25, 2008 (4:35 pm)
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There's a good ride and drive report on the writer's time in the new Jetta TDI. It's a good fair appraisal IMO.
Jetta TDI
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- #7221 of 8144
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Local Prices 11/25/08
by altair4
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Nov 25, 2008 (6:09 pm)
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RUG down to $1.999 with Diesel at $3.109. Price spread as a percentage currently rules out the Jetta CleanDiesel as a viable alternative for a replacement to our aging Accord.
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- #7222 of 8144
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Re: ... Diesel Design Thoughts [roland3]
by roland3
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Nov 27, 2008 (2:10 am)
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Replying to: roland3 (Nov 22, 2008 6:26 am)
... If you look "fuel claims polarise opinion" in Google News you will see some controversial fuel droplet research conducted by Professor Tao of Temple University. This is quite a bit related to the theory behind Green Diesel Corp's new injector; however one relying on a mechanical means and one system using an electronic method to achieve the same goal, more complete fuel combustion. I think there should be some regulation induced incentive for these very sophisticated Diesels in that for reduced carbon and soot output there might be a Diesel only reduction (not to apply for gasoline engines) in the NOx regs that are strangling the industry.
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- #7223 of 8144
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Re: ... Diesel Design Thoughts [roland3]
by winter2
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Nov 28, 2008 (7:44 pm)
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Replying to: roland3 (Nov 27, 2008 2:10 am)
Interesting comments. An interesting issue here. As gasoline engine compression ratios increase, and more of them are moving toward direct gasoline injection, they are starting to run into some of the same issues diesels have had, namely particulate and NOx. Higher compression ratios are more conducive to the formation of NOx. Particulate in direct injection gasoline just may become a problem. Particulate comes from the incomplete combustion of fuel. In gassers, add the fact that sulfur content is 30 PPM versus less than 10 PPM for U.S. diesel fuel, you add to the particulate issue. Granted 30 PPM is pretty small, but considering that 97% of vehicles in the U.S. are gasoline powered, it adds up.
In the newer diesels, piezo-electric injectors are becoming more mainstream. They can inject seven plus injections quickly to cool the air charge and produce a very clean burn. As for particulate, there are self-regenerating particulate exhaust filters and appropriate catalysts and urea spray systems to reduce NOx.
Does anyone in the forum know how effectively the urea injection system reduces NOx?
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- #7224 of 8144
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Re: ... Diesel Design Thoughts [winter2]
by ruking1
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Nov 28, 2008 (7:54 pm)
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Replying to: winter2 (Nov 28, 2008 7:44 pm)
Here's a start.
link title
link title
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- #7225 of 8144
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Re: ... Diesel Design Thoughts [winter2]
by roland3
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Nov 28, 2008 (8:46 pm)
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Replying to: winter2 (Nov 28, 2008 7:44 pm)
... As far as I know the piezo-ceramic, CR injection systems have a max of five pulses. Because they are injected into the combustion chamber and instantaneously ignite, the systems have no effect on the intake air temperature.
..
... The urea after-treatment systems are very effective on reducing NOx; however it is my opinion that the entire infrastructure will have to work, almost without problems, for two years, after implementation, just to cover, the carbon footprint, from building, the hundreds of millions of dollars, infrastructure, where upon, I expect the whole system to be obsolete. At least, it does not appear to be outright poisonous, as the MTBE debacle was. The reduced carbon output is a trade off in that urea treated engines are more efficient, because they can be tuned and built to a higher state and make more heat. Of course, that is if you ignore the three percent liquid penalty of the urea, and what it took, to get it, in your car.
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- #7226 of 8144
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Re: ... Diesel Design Thoughts [roland3]
by winter2
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Nov 29, 2008 (5:32 pm)
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Replying to: roland3 (Nov 28, 2008 8:46 pm)
Here are links showing piezo injection with seven pulses.
http://www.greencarcongress.com/2008/09/delphi-launches.html
Here is another.
http://www.springerlink.com/content/h5g70142565u5131/
Here is yet a third showing up to seven injections/cycle
http://www.theengineer.co.uk/Articles/268707/Perfect+piezo.htm
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- #7227 of 8144
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Re: ... Diesel Design Thoughts [ruking1]
by winter2
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Nov 29, 2008 (5:42 pm)
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Replying to: ruking1 (Nov 28, 2008 7:54 pm)
Based on the first link, NOx cannot exceed 0.05 gm/mile. If I could retrofit such a system onto my Jeep Liberty CRD, then it would reduce NOx by 88% and for the new Jetta TDI by 82% to meet the 0.05 gm/mile.
On the British version of our EPA website, a brief search shows no diesel using AdBlue or equivalent. Many do have DPF though.
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- #7228 of 8144
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Re: ... Diesel Design Thoughts [winter2]
by gagrice
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Nov 29, 2008 (8:03 pm)
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Replying to: winter2 (Nov 29, 2008 5:42 pm)
The Jetta TDI passes all emissions without adblue. Only the V6 diesels coming from BMW and Mercedes use adblue to get 50 state approval. Honda tried without it and failed the test. So I've read. Honda claims it would cost $5000 more for the diesel than gas engine to pass California emissions. VW is doing it for about $1200.
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