[MarkJ]

Having said which, you can also run them on domestic heating oil; which gives anyone who has a diesel car & an oil heating tank the option to hoard a lot of motor fuel very quickly (grin).

JP

Diesel, kerosene, heating oil, off-road diesel etc are also more secure and face less condensation issues in basement tanks.

[RdSnt]

We had 50mpg diesels in the 70's
Low sulfur fuels require additional processing (read more energy input) thus negating any gain in efficiency in the engine.
Keep in mind that 38% gain is based from an engine/drivetrain that converts fuel to traction horsepower at about 12%

Diesel engine advancements may increase efficiency of currently existing systems, especially when coupled with the use of low-sulfur diesel or biodiesel.
According to this article from Matter Network, new diesel engines are quieter and get better fuel economy- some up to 50 mpg!
This article from AutoBlogGreen highlights the winners of Challenge X- Mississippi State University powered a Chevrolet Equinox to a win by coupling a hybrid electric system and a diesel engine (which ran on biodiesel). With a 38% efficiency gain, they demonstrated that this match may just be one worth looking into.

[gollum]

Diesel fuel stores longer and is safer, also you can mix in a little kerosene in a diesels tank without any harm, and even a small amout of gas (say 1:50) and usually be ok. Older diesels are pretty versitle.

However diesels are harder to start in cold weather. All things being equal I think the ideal combination is a diesel truck and a small gas car.

[gollum]

Diesel fuel stores longer and is safer, also you can mix in a little kerosene in a diesels tank without any harm, and even a small amout of gas (say 1:50) and usually be ok. Older diesels are pretty versitle.

However diesels are harder to start in cold weather. All things being equal I think the ideal combination is a diesel truck and a small gas car.

[yesplease]

We had 50mpg diesels in the 70's
Low sulfur fuels require additional processing (read more energy input) thus negating any gain in efficiency in the engine.
Keep in mind that 38% gain is based from an engine/drivetrain that converts fuel to traction horsepower at about 12%

Sources? According to fueleconomy.gov, the difference between identical vehicles, one w/ a gas engine and one w/ a diesel engine, is significant. For instance a 05 diesel powered Jetta pulls ~46% better mileage, adjusted for energy content, than the 05 gasoline powered Jetta. According to ANL,as of 2006, with ULSD being the primary distillate w/ higher sulfur diesel only available for off-road use, the refining energy efficiency of diesel was still higher than that of gasoline. So... Not only are diesel apparently more efficient in identical models, but diesel production itself is as well.

[skeptik]

Diesel engine advancements may increase efficiency of currently existing systems, especially when coupled with the use of low-sulfur diesel or biodiesel.
According to this article from Matter Network, new diesel engines are quieter and get better fuel economy- some up to 50 mpg!

To a European, it's surprising that you are surprised at this. Check out the stats in the first table on this page.

http://www.fuel-economy.co.uk/stats.shtml

The car I've been driving for over a year now (yes, that is me. Greying beard, 6'1" tall) ) is a compact 4 door 4 seater hatchback, the Citroen C3 1.4HDi which is quoted as having a combined cycle MPG (average of city and highway UK govt test) of 67.30 MPG (note this is Imperial gallon, not US gallon. 1 UK gallon = 1.2 US gallon)

In use , with low sulphur diesel (2 grades of diesel and 1 grade of gasoline, regular unleaded, is standard in most Spanish gas stations) and a catalytic converter to burn off soot particles, it's no different to a small petrol engine car, except it's less whiney - much better torque at low revs.

[criticalmass]

If this little diesel lives up to the claims, it is a HUGE step in the right direction. This is almost "old" technology already. Hs anyone seen it in anything tangible yet?

http://angellabsllc.com/

[CarlosFerreira]

I regularly get 50 mpg in my diesel (VW Polo 1.4 TDI), in my father's diesel (VW Golf 1.9 TDI) and in my girlfriend's diesel (Renault Megane 1.5 DCI). That's just keep a steady 55/60 mph. It's really no big deal. Let's just expect hitting 75mpg anytime soon.

[Denny]

Check out this article, it claims auto use for diesel is being doomed by the complexity and cost of the emission controls.

That is surprising, as diesels ars so popular in Europe and you would think with their population density, they would have even more stringent emissions laws than the U.S.

Wards - Diesel: DOA in the USA?

[otter]

Does anyone have an estimate on the volume of gas and diesel used in Denver, or Colorado if Denver info is not available.

[BicycleCommuter]

Begin by checking out the Denver Region Council of Governments (DRCOG). They model VMT and vehicle trips for the region and maybe able to provide a figure.

For Boulder, Colorado (more precisely the Boulder Valley Comprehensive Planning area) we see about 2.4-2.7million VMT per day. Typically use an average MPG of 19.5 and therefore people living in and around Boulder consume about between 123,000 and 138,000 gallons per day if my calculations are correct.

[Gerben]

Original article:
http://www.news.wisc.edu/16945
(credit to kjmclark for pointing me to this article in another thread)

Extract with some clarifications added by me.
The engine research group at the University of Wisconsin-Madison is blending diesel and gasoline showing significantly lower pollutant emissions than conventional engines, with an average of 20 percent greater fuel efficiency.

Diesel and gasoline both bring unique assets and liabilities to powering internal combustion engines. Diesel engines operate more efficient than gas engines, but gas engines burn cleaner. The new engine blends the fuels inside the combustion chambers at precisely the right mix. Diesel is used to ignite the gasoline.

This provides the following advantages:
First the engine operates at much lower combustion temperatures because of the improved control — as much as 40 percent lower than conventional engines — which reduces heat loss.
Second, the fuel preparation controls the chemistry for optimal combustion. That translates into less unburned fuel energy lost in the exhaust, and also fewer pollutant emissions being produced by the combustion process. The lower emissions allows for meeting EPA's 2010 emissions without additional cleaning.
In addition, the system can use relatively inexpensive low-pressure fuel injection (commonly used in gasoline engines), instead of the high-pressure injection required by conventional diesel engines.

Comment:
This is technically similar to CNG/diesel dual fuel operation. Gasoline however is more widely available than CNG and has a similar energy content by volume compared to diesel (no negative impact on vehicle range).
It is the combination of higher efficiency and low emissions that makes this technology seem viable. Diesel engines have a hard time meeting the same emissions that are feasible with other fuels. Diesel engines operate more efficiently, but are also more expensive. This new engine is basically a diesel engine, so it's probably going to be expensive, but the fuel economy compensates for that. In comparisson to other engines that meet the EPA 2010 emissions this looks like a winner to me.

[kjmclark]

No, this is much cooler than your description sounds. This engine and others like it will probably end up in just about every car/truck in ten years or so. (Unless we wisely switch to serial hybrids and turbines by then.)

First, all internal combustion engines are heat engines. An important part of how they work is in transferring heat. The thermal efficiency is an indicator of how close an engine is to the theoretical limit of how efficiently an engine can burn fuel. For comparison, this engine burns at about 53% thermal efficiency. This Wikipedia article points out that most gasoline car engines are only 25% thermally efficient, the best diesel engines are only about 52% thermally efficient, and the best thermal efficiencies overall are combined heat/power systems, at around 60% efficient, because they reclaim the heat for another use (heating).

But the kicker is that the engine does this with cheap technology, even cheaper technology than is used in regular diesel engines. They basically hooked up a computer chip, a small diesel engine with an extra set of fuel injectors, cheap automobile fuel injectors, and two fuel tanks. Diesels are already cheaper to maintain than spark ignition engines. So what you end up with is an engine that you can sell in the US tomorrow, that's as cheap as a small diesel now, but that gets 20% better mileage than a regular small diesel, and meets US particulate emission requirements easily.

The only problem with it is that when you pull up at the filling station, you'll have to either use two different nozzles, or the filling station industry will have to come up with a dual nozzle that fills both tanks at once. So, for the hassle of filling two tanks when you go to the station, you can get 40mpg in your small SUV, 60mpg in your standard sedan, or 80mpg in your fuel-sipper.

[Gerben]

Note that the 53% is under optimal conditions and not during normal operation. The difference between an optimal diesel engine and the optimum for this engine is small. They get a better result than with normal diesels, but I doubt they will constantly achieve significant improvement during normal operation. A CNG/diesel engine runs on pure diesel when warming up, so then it's just an old-fashioned diesel engine (no emission gains either!). I expect this to be the same for this one.

I'm driving an old fashioned diesel car. No turbo's and stuff, similar to the engine block they use. I sometimes blend in some gasoline to make the car run better with vegetable oil.
Modern diesel engines work with higher pressures because that allows them to get more power out of the same cylinder volume. Lower pressures are not necessarily an advantage. It means you need larger cylinders, resulting in a heavier engine. With normal diesels this heavy engine and the adaptations this requires to the car make it cheaper and more efficient to have a lighter turbo charged diesel. Old fahioned diesels are also noisy and need time to warm up. I like this engine, but I'm not yet convinced it is as cool as you think.

[Gerben]

Dual fuel would not save petroleum and is not a peak-oil mitigation. Both liquids are factions of the same limited crude.

Higher efficiency saves fuel and that's one of their objectives.

[Frank]

I know that a gallon of diesel has 20-25% more BTU's available than a gallon of gasoline but how many gallons per barrel can you get of each? I seem to remember that a barrel can produce 42 US gallons of gasoline. How about diesel? You can't make energy that's not there in the first place. This is to help me formulate a response to a letter-to-the-editor in a local paper whose author thinks switching to diesel vehicles en masse is a good solution.\

TIA

[SteinarN]

How many gallons of each vary with the quality of the crude. Light crude yelds more gasoline from each barrel of crude than do heavier crude. Heavy crude yelds significantly more diesel than gasoline from each barrel. Nowadays a large part of the gasoline is made by cracking the heavy residual crude left over from the normal destilling process. This cracking may involve the addition of steam at a high temperature and pressure in the presence of a catalytic substance. The cracking itself causes a loss of some (external) energy so even though the mass and energy content of the total amount of diesel versus gasoline obtained from one barrel of crude is the same, the energy input to the cracker already at this point causes the net energy from a barrel of gasoline to be lower than the net energy from the same mass or weight of diesel.

Further a diesel engine has a substantial better thermal efficiency than a gasoline engine. The fuel consumption measured in volume is in the neighborhod of 30% lower in a diesel engine than a gasoline engine. Even measured in mass or weight the fuel consumption is at least 10-20% lower in a diesel engine.

This means that one barrel of crude refined to diesel can propel a car 10-20% longer distance than the same amount of crude refined into gasoline. In addition the cracking necessary to produce a large part of the gasoline causes increased consumption of electricity at the refinery, alternatively the refinery has to burn some of the heavy residuals left over from the normal destilling process, to produce the required heat, which otherwise could have been cracked to yeld more fuel. When taking this energy consumption into consideration it is fair to say that the net energy from one barrel of crude refined into diesel can propel a car 20-40% longer distance than the same amount of crude refined into gasoline.

[jeromie]

For general purposes, crude oil using catalytic cracking and a number of variants will yield the classic rule of thumb 321. That is, without accounting for additives or losses, 21 gallons of light distillates , 14 gallons of middle distillates and 7 gallons of everything else. Light distillates will yield around 17 gallons of gasoline with around 4 gallons of aviation gasolines and valuable naptha.

Middle distillates are fuel oils, diesel , kerosene, and heating oil.

Everything else yields , motor oils, greases, waxes, and at the bottom asphaltum and bunker fuel.

Of course , much blending is possible to create tailored fuels.

What is so interesting about crude oil refined product usages is the fact that the truly essential uses in the economy are the middle distillates. The vast bulk of middle distillates are consumed in goods transportation and heating homes. There are still 8 million homes heated by heating oil plus a lot of commercial buildings heated by oil. The diesel locomotive being king means all rail transport depends on diesel fuel. Then there is over the road trucking as well as local distribution.

No matter what you do, middle distillate oil usages are critical with only the personal use diesel fueled car being discretionary usage based on the way our producing and distribution of goods portion of the economy is actually organized. Thus cutting oil imports means , first of all , elimination of home and commercial fuel oil heating. The production of light distillates that is a total by product of middle distillate critical needs is around 150 % of total critical use middle distillate needs. Thus, the gas guzzler burns marginally what is produced automatically and might only be exported without the gas guzzler. Absent the gas guzzler from the US without middle distillate changes and there would be a gasoline glut in the world. The refiners could not stay in business if gasolines were a chronic glut.

Thus the whole SUV gas guzzler set of hatreds is so much hot air.

Of course, if middle distillates were curtailed by forced substitution of gas for present heating purposes 150 % of that shrinkage would occur in gasoline and naptha production.

If the foregoing were put into practice, our marginal shrinkage in crude oil imports would freeze out most or all imports outside of Canada and Mexico.

Such a development would eviscerate the Petrodollar recycling system and that process eliminate foreign financing of US Treasury deficits. US imports of crude from the Persian Gulf are critical to financing the Treasury at any level since the advent of Reagan.

The old 321 rule is just an approximation but again in a backhanded way to increase middle distillate values by blending light distillates with middle distillates.