Recent Comments:
Popular Mechanics samples the Audi TT TDI {Autoblog Green}
Aug 4th 2008 10:58PM LEV II = Tier 2 Bin 5.
ULEV II is a category below LEV II and does not directly equate to a specific Bin.
The 2009 Jetta not only meets ULEV II, it meets Bin 4 in all regulated categories. It hasn't been officially certified by EPA yet, but it APPEARS it will meet Bin 4 based on CARB's certification.
Popular Mechanics samples the Audi TT TDI {Autoblog Green}
Aug 4th 2008 8:20PM 1985 Gripen -
You make several good points. The difference in fuel cost (unjustified based on everything I've seen) will likely impede LD diesel sales in the U.S.
Regarding emissions, ground-level ozone (the primary constituent of "smog") formation requires both NOx and hydrocarbons (NMHC). CO also can contribute since it behaves like NMHC in the atmosphere - only generally less reactive.
Ambient conditions encountered in virtually all urban/suburban areas in the U.S. ("VOC-limited") favor DESTRUCTION of ozone (smog) by NOx emissions, so control of NMHC/CO emissions is much more effective.
Diesel vehicles tend to be inherently low in NMHC and CO emissions, plus have very low evaporative emissions (a major disadvantage of gasoline vehicles), so a significant penetration of the T2B5 diesel vehicles could potentially improve air quality in many locations.
Furthermore, it is unlikely that a auto manufacturer will introduce any LD diesel vehicles in the U.S. that are not at least T2B5. Based on 2009 CARB certification data, the clean diesel vehicles may hit Bin 4 and even Bin 3 (they're certified "ULEV II" in California).
VW's new Jetta TDI now eligible for $1,300 federal tax credit {Autoblog Green}
Jul 28th 2008 12:58PM To add to what Sam said, there's actually much more "straight run" (naturally occurring) middle distillate (i.e., diesel) than "straight run" gasoline in a barrel of crude oil - http://www.theoildrum.com/node/2174 . The current refinery yields are the result of how our refineries are currently configured. This current configuration is one reason why the diesel fuel in the U.S. is of relatively poor quality - a significant portion of the straight run middle distillate is "cracked" into gasoline, and the middle distillate shortfall is made up from "light cycle oil" which is a low-quality middle distillate "cracked" from heavier fractions. LCO is low quality in the sense that it has low cetane - about 20-25. Straight run diesel has a cetane of 50-55. Diesel fuel sold in the U.S. typically has a cetane of 40-45.
Furthermore, several petroleum companies (e.g., Marathon, Shell, Valero) have indicated that they intend to expand their production to convert more crude oil into diesel and less into gasoline (equal amounts and even more diesel than gasoline in some instances) since diesel is now seen as a more valuable product that gasoline (the "silver lining" to the relatively higher cost of diesel vs. gasoline, I guess).
VW's new Jetta TDI now eligible for $1,300 federal tax credit {Autoblog Green}
Jul 25th 2008 9:38AM If you click on the "gas pump" icon in the right margin of your link, it says "Refining Costs & Profits" under "Methodology For Gasoline and Diesel Fuel Pump Components", so we don't know how much is refining costs and how much is profit.
By all accounts, diesel fuel not only costs less to refine ( http://www.leftlanenews.com/mercedes-exec-says-big-oil-conspiring-to-kill-us-diesel-market.html#more-7725 , http://www.nefi.com/oilandenergy/QandA_Jan08.html ), it requires considerable less energy to produce (less than half as much energy per BTU of product per UC-Davis - http://www.its.ucdavis.edu/publications/2003/UCD-ITS-RR-03-17-MAIN.pdf ).
VW's new Jetta TDI now eligible for $1,300 federal tax credit {Autoblog Green}
Jul 24th 2008 1:46PM In most areas that have a "smog" issue, yes, hydrocarbons are the cause, NOT NOx. NOx actually destroys ozone (which is the principle component of smog) in the "VOC-limited" regimes (all urban locations studied so far are VOC-limited), so lowering ambient NOx levels relatively more than ambient HC levels actually results in higher ozone levels (i.e., more smog).
In very simple terms, NOx "makes" ozone, HC (and CO) allow it to accumulate in the atmosphere.
VW's new Jetta TDI now eligible for $1,300 federal tax credit {Autoblog Green}
Jul 24th 2008 11:18AM The emission issue is a canard. PM emissions have been virtually eliminated.
You may get marginally higher NOx emissions with these T2B5 diesels (although still near zero), but you get lower HC/VOC emissions. HC emissions are the cause of high ozone levels in urban areas, not NOx.
Many dealers report selling out of Jetta TDI, Tiguan TDI possible {Autoblog Green}
Jul 16th 2008 11:42AM Mr E - actually, the 2009 Jetta TDI has less "smog forming" emissions than even the squeaky clean Prius based on the CARB certification data if you take evaporative emissions into account (which definitely should be included).
You guys are being brainwashed by environmental groups into thinking only NOx is "smog-forming". HC and CO emissions are also "smog-forming".
Euro-spec BMW 335d rated at 35 mpg (US) combined {Autoblog Green}
Jul 14th 2008 2:57PM brn - I think Richard got his information from EPA's "Final Technical Support Document
Fuel Economy Labeling of Motor Vehicles:
Revisions to Improve Calculation of Fuel Economy Estimates", http://www.epa.gov/fueleconomy/420r06017.pdf page 8 [16 of 179].
Also note in Table III.A-28 on page 90 [98 of 179] that a correction factor is applied to ALL vehicles, including diesels, for "fuel quality" which is a correction for ethanol in gasoline (see page 82 [90 of 179]).
New BMW 7-series hybrid uses lithium, still won't match efficiency of diesel {Autoblog Green}
Jul 9th 2008 11:56PM According to documentation of UC-Davis' "Lifecycle Emissions Model" (LEM), ultra low sulfur diesel (ULSD) fuel with 5 ppm sulfur by weight requires an average of 0.0812 BTU per BTU of product while reformulated gasoline requires an average of 0.170 BTU per BTU of product.
http://www.its.ucdavis.edu/publications/2003/UCD-ITS-RR-03-17-MAIN.pdf
Spy Shots: Diesel powered Volvo XC60 spotted testing in LA {Autoblog Green}
Jul 8th 2008 10:09PM Mr E,
Understood, although the difference in NOx emissions between the 2009 Jetta TDI and the 2008 Prius is more like 5 times (0.05 g/mi v 0.01 g/mi). But the difference in HC emissions is much higher in the Prius, especially if the evaporative VOC emissions from the storage and distribution of gasoline are taken into account.
Greenhouse gas emissions are probably a wash because of the higher energy requirement to refine gasoline vs. diesel fuel, plus the somewhat higher emissions of N2O and CH4 (both strong greenhouse gases) typical of gasoline engines (http://epa.gov/climatechange/emissions/downloads06/07Energy.pdf Tables 3-23 and 3-24).
According to several reports I've seen, the cost of a diesel powertrain is typically less than a hybrid powertrain even if you include the higher cost of emission control on the diesel (see, e.g., http://www.ricardo.com/download/pdf/R119361S.pdf , http://www.rand.org/news/press/2007/11/08/index1.html ).
I guess I don't see what's wrong with having MORE choices (including LD diesel and hybrids). Choice is a good thing, isn't it?
