Comments on: Diesels Make Strong Presence at LA Auto Show

By: Bryce

Bryce — Mon, 01 Dec 2008 06:38:28 +0000

People also seem to forget that Diesels come with an added cost of purchase for the diesel engine. Once you add that to the higher fuel costs, then I would expect it is a net loss relative to a gas engine. I like diesel, but mostly for commercial applications that use the engines to their full potential and life cycle. A regular commuter doesn’t really use the engine to its max, where its cost efficiencies would be found.

By: Shines

Shines — Mon, 01 Dec 2008 04:39:26 +0000

OK I noticed the size of the Jetta is compact.
So the vehicles to compare it to would be the Corolla and Ford Focus. The Jetta is more fuel efficient than either, but the fuel cost difference ends up in favor of the Focus and Corolla.

As far as how much diesel is in a barrel of crude - depends.
The light sweet crude that the US mostly buys is I believe about 20% diesel and 40% gasoline. This means that simply cracking the oil (splitting it into its basic compounds (the least expensive way to extract the compounds in it)) will yield a lot more gasoline. However, refineries can chemically alter the oil to produce more diesel, but that costs more.

Then there's the government taxing diesel more because it is used mostly by big rigs which put more wear and tear on the roads...

By: Jason

Jason — Sun, 30 Nov 2008 14:49:43 +0000

Using the nationwide average price for diesel versus the average price for 87 octane gasoline, I would save money with the VW Jetta over the current average mpg of my 2004 Toyota Tacoma. So, even with diesel prices being higher, I would spend less money at the gas pump by driving the Jetta. If you are really interested in what the cost benefit of diesel over gasoline is, then I suggest doing a little research and some math and figuring it out relative to a vehicle you are driving now. Also, where I live, diesel is not even close to 50% more expensive then gasoline, fwiw.

By: Jakub Kudlacz

Jakub Kudlacz — Mon, 24 Nov 2008 20:12:34 +0000

Diesel is 35% more fuel efficient, more powerful and it costs 25% more. Also keep in mind, that economies of scale are at work here. More diesels on the market cheaper the fuel.

Also Diesel engines will outlast your gasoline engine anytime, so you can drive that car so much longer.

By: Paul Beerkens

Paul Beerkens — Mon, 24 Nov 2008 17:44:09 +0000

I would like to place one order for a Opel Flextreme please.

By: wxman

wxman — Mon, 24 Nov 2008 15:26:38 +0000

I’ll acknowledge that I have no special expertise in petroleum refining, but it’s counter-intuitive that more diesel couldn’t be produced from a barrel of crude than gasoline, especially the “heavy” crudes (which apparently are becoming increasingly more common).

According to several references I’ve run across (e.g., http://www.theoildrum.com/node/2174 ), nearly 80% of “heavy” crude is middle distillate (i.e., diesel) or heavier. Naturally-occurring (“straight-run”) gasoline actually makes up a very small percentage of crude oil (MUCH less than straight-run middle distillate), especially for “heavy” crude oils, so obviously most gasoline comes from “cracking” heavier components of crude oil. Why can’t the cracking process be controlled so that only middle distillate is produced? It would seem that well over half of a barrel of crude potentially could be refined into diesel rather than gasoline (just reduce the intensity of the “cracking” process).

That appears not to be the case since otherwise refiners should be falling all over themselves to produce more diesel, since it is selling at a much greater profit than gasoline right now. Does anyone have any insight into this conundrum?

By: Dom

Dom — Mon, 24 Nov 2008 14:31:00 +0000

Go VW!! I'm happy to see the clean diesel finally getting some real recognition. What the diesel nay-sayers fail to realize is that hybrids aren't always the best fit for a given application, and the same goes for diesel. They both have strengths and weaknesses. Also, the article doesn't mention it, but the VW Jetta TDI Sportswagen is the ONLY wagon available that gets 40+ mpg. Go VW!!

On a different note, that Opel sounds very interesting.

By: sean t

sean t — Mon, 24 Nov 2008 12:49:28 +0000

Nothing is wasted if you do diesel or gas, but the point is the total value of a whole barrel of crude oil if you extract diesel against the same thing for gas. In brief, what matters is the total value of the products and sub products.
I think the other products are different from extracting gas and diesel so I guess you have to balance how much crude oil should be used for diesel or gas.

By: Bryce

Bryce — Sun, 23 Nov 2008 17:31:32 +0000

you are right though. In a barrel of crude, about 40 gallons of gas can be milked out. Out of a barrel of crude, about 20 gallons of diesel can be pulled out. However, I don't think necesarily that the whole barrel of crude is wasted if you do diesel, in fact rather, both crude and diesel are filtered out of the crude along with other combustibles like Butane, Propane, and the like. So, I think in that sense, it doesn't matter.

Someone, please correct me if I am wrong.

By: RTH

RTH — Sun, 23 Nov 2008 16:45:25 +0000

I'm far from an expert on these matters, but why do these articles touting the high mileage of new diesels never mention that it's basically unfair to compare MPG estimates for gas engines vs diesels. A better comparison would be miles per gallon of crude oil used to make the fuel.

According to the Union for Concerned Scientists web site, it takes more crude oil to make a gallon of diesel fuel than it does to make a gallon of gas (and diesel has a higher energy content per gallon as a result). UCS recommends deflating the MPG estimates for diesels by 20% in order to compare them with gas-powered cars on the more realistic basis of the amount of crude oil each uses.

Doing that for the new diesel Jetta mentioned above reduces its 41/30 MPG estimate to about 33/24, which is certainly an improvement over gas Jettas but is also far from Prius territory.

I should add that I have nothing against diesels (in fact, I am sorely tempted by the diesel Jetta wagon), but I never see these factors mentioned in discussions of diesel mileage.

If I'm way off-base here, somebody please correct me.