the single most effective thing we could do

[jamesqf]

I think switching to diesel would be impractical due to refining technology. You can only get a certain fraction of diesel (and gasoline) from oil. Diesel used to be cheaper than gas because there was less demand for the diesel fraction: now it's more expensive due to increased demand.

But in the long term, both diesel and gasoline IC engines are less than optimally efficient. Stirling engines can get significantly more useful energy out of each gallon of fuel than either. Their drawback has been that they are slow to warm up & accelerate, but combine them with a hybrid electric drive and that limit goes away, and the hybrid adds fuel savings from regenerative braking.

In the short term, though, the single change that would produce the greatest savings is to mandate that every car have a real-time fuel consumption gauge :-)

[Frank Lee]

The single most effective things we could do are eliminate dependent tax deductions and change the school funding formula so that parents pay it. But that will never happen.

[ttoyoda]

change the school funding formula so that parents pay it.

No, because if all parents had to pay for school directly, far far more of them would demand a lot more performance and accountability. Far more parents would start to pay close attention to what is being done to their kids at school. The magnitude of THAT feces-storm would be so huge that the whole school system would be overhauled, by parents with torches and pitchforks, from top to bottom. And that would step on important toes.
People don't ask too much of things they "think" of as "FREE"

[Frank Lee]

Sounds good to me!

[tjts1]

Diesel is losing market share due to the high cost of fuel in America
http://blogs.automobilemag.com/62511...tum/index.html
And Europe
http://www.autobloggreen.com/2008/06...otential-buye/

A bit of surprising news comes from Germany, where one out of four diesel owners state that their next new car will likely be a gasoline vehicle, thanks in part to the complexity of owning a diesel and the high repair costs. Things even look worse for old models: those cars not fitted with Diesel Particulate Filters aren't likely to be purchased second hand (and will probably end up in Southern Europe), mostly due to the restrictions in some cities.

Diesel emissions in European cities have been a disaster. Try going walking a few miles around Barcelona in August. I have. Its worst than LA.
http://www.cardiffcyclingcampaign.or...article&sid=32
http://www.iht.com/articles/2005/09/21/news/air.php
http://www.spiegel.de/international/...349918,00.html
http://www.hybridcars.com/diesel/die...t-attacks.html

The health effect of biodiesel exhaust emissions are unknown.
http://www.greencarcongress.com/2007..._research.html

Gasoline contains 115,000 Btu, while diesel contains 130,500 Btu or 12% more energy. Not the 40% some people around here like to claim. The rest of the perceived difference in FE comes from compression igntion cycle vs the spark ignition cycle. A compression ignition HCCI gasoline engine is 15% more efficient than current spark spark ignition engines without the need of expensive particulate filters.
http://www.greencarcongress.com/2008...tinues-to.html

http://www.youtube.com/watch?v=FOKZBAJM180

You can extract much more gasoline than diesel fuel from a barrel of oil.
http://www.energy.ca.gov/gasoline/im...rel_of_oil.gif
It takes more crude oil to produce the same amount of diesel fuel as gasoline.

Diesel doesn't have a future in passenger cars.

[IndyIan]

I am trying to imagine being stuck in traffic around Toronto with every car being a 2005 diesel Jetta It would smell pretty bad, but probably more people would use public transport because of it.
I do agree that way less fuel would be used, especially in traffic jams as a diesel jetta beats nearly everything but a hybrid in city MPG and highway MPG. If we could get them to the emmisions level of gas cars then I would be all for it.

The health effect of biodiesel exhaust emissions are unknown.
http://www.greencarcongress.com/2007..._research.html

Is working over a deep fryer a health and safety risk? Biodiesel is usually cut with 1% "real" diesel because that makes it toxic enough to prevent mould or other biological problems. I would bet on biodiesel emmisions being better.

You can extract much more gasoline than diesel fuel from a barrel of oil.
http://www.energy.ca.gov/gasoline/im...rel_of_oil.gif

One of the comments in the first link I quoted was that portions of that barrel that could be more easily made into diesel are cracked into gasoline because of the demand for gasoline.

Anyways, I think the long term solution is to have vehicles that use 1/4 as much fuel and then you can run your diesel on straight veggie oil or run on electricity from your solar panel array or whatever without creating as much pollution and greenhouse gases. GM should just mass produce something like the Aptera, save their own company and the envrironment all at once. If they can afford to lose the billions they are now, why not add 1 billion more and develop and produce something like that. I'd have to think the engineers at GM with a billion dollars could create something that would out perform the Aptera and cost half as much... They have the dealer network that is screaming for somehting they can sell and willing to try anything at this point.
I guess it would make to much sense, and besides the Aptera looks "funny".
Ian

[JJW]

Actually, the single most effective thing we could do to reduce fuel usage, short of getting rid of the SUVs, would be to reinstate and enforce the national 55 mph speed limit (well, if by "we" you mean "the US" ) However, I don't know too many people in favor of that.. even though I travel at that speed most of the time, I don't like laws. But, it would be about a 10% increase in overall efficiency, and not require people to change their vehicles. Just their habits.

[ttoyoda]

Sounds good to me!

Yes, it would be nice if each new generation knew everthing their parents did, PLUS the newest technical information. Maybe there would be time for this in the school day if we reduced the lessons relating to "National Guilt Week".
must. stop. now. blood. pressure. exceeding. nominal. limits.

[tjts1]

Originally Posted by jamesqf

In the short term, though, the single change that would produce the greatest savings is to mandate that every car have a real-time fuel consumption gauge :-)

+1
Every car should have a trip computer like this.

Average MPG. Instant MPG is only displayed when the car is moving.


Average speed. On this particular trip I did 50 miles at 65mph, 35miles at 55mph and 5 miles in stop and go traffic.


Miles coved.


Estimated miles to empty at average MPG.


This is on a 12 year old Volvo. I think its shameful that every car today doesn't have this kind of display. This base model Volvo 850 wagon 5 speed didn't come with it from the factory. It was optional on higher end models. I found one at the JY and the installation was simply plug and play into the existing instrument cluster.

[jamesqf]

Originally Posted by JJW

Actually, the single most effective thing we could do to reduce fuel usage, short of getting rid of the SUVs, would be to reinstate and enforce the national 55 mph speed limit...

An idea that (in addition to all the other problems) suffers from over-generalization. For instance, on my route into town there is a small hill. I let my speed drop to ~45 mph going up (limit is 50, most traffic is 55-60), increase to about 65 on the downhill, and semi-coast to the light about a mile down the road. In good weather I can average over 100 mpg on this stretch. If a 55 mph limit was strictly enforced, I'd have to ride the brakes on the downhill (as I see many doing), wasting energy and getting lower overall mpg.

Or take another example: on my drive from Reno to San Jose, I go over an 8500 ft pass, then the next 70 miles or so is all downhill, and I effectively use zero gas on this stretch. Why should I be limited to 55 there, in order to "save gas" that I'm not using?