transportable fuels

a briefing document

site map

Index
Introduction
Transportable fuels
Discussion
Fuel consumption comparison table – US-oriented
Fuel consumption comparison table – UK-oriented
Top-rated road vehicle fuel consumptions in the USA, 2003
Conversion tables for imperial gallons, US gallons and litres
Dodge city – is the USA quite mad?

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Transportable fuels

A useful, if sketchy, introduction to the replacement of present transportable fuels as the pumpable oil supply shrinks. The article concentrates mainly on the advantages of ethanol over hydrogen in the near term, with references to various hybrid vehicles.

“The hydrogen-fueled transit vision being peddled in Washington and Sacramento obscures a more achievable alternative.”

The point is to substitute for petrol and other transportable fossil-derived fuels.

‘Petrol’ or ‘gasoline’ is a complex mixture of hundreds of different hydrocarbons.

Ethanol is what is more widely know as alcohol (booze!) or as grain alcohol. Methanol is known widely as wood alcohol or methylated spirits.

Alcohols are among the more abundantly produced organic chemicals in industry. Some, such as ethanol and methanol, are manufactured and used in great quantities.

Methanol and ethanol are good fuels for automobile engines because they have high octane ratings and low pollution emission. Gasohol, a solution of 10 percent ethanol in gasoline, is an alternative fuel that can be used in most automobiles.

For formation of methanol from electricity, air and water (pdf file).

Howstuffworks.com is a useful site providing information and diagrams, such as the next two links.
Here is a nice moving illustration of a diesel engine.
This is a good place to start exploring if you are interested in the chemical stuff about transportable fuels.

Gasoline, or petrol, is an aliphatic hydrocarbon. That is, it is made up of molecules composed of only hydrogen and carbon, which are arranged in chains. Gasoline/petrol molecules have from seven to 11 carbons in each chain.

Note that with less carbon (and hydrogen) in the chain, the molecule is lighter. With from one to four carbon atoms, the aliphatic hydrocarbon is a gas – methane (CH4), ethane (C2H6), propane (C3H8) and butane (C4H10). With from five to 18 carbon atoms, the molecule is a liquid; while with 19 or over carbon atoms, the molecules are all solids at room temperature.

    H H  H H H H H  H H H
     |   |    |   |   |   |   |    |   |   |
H-C-C-C-C-C-C-C-C-C-C-H Decane [10]
     |   |    |   |   |   |   |    |   |   |
    H H  H H H H H  H H H

Discussion

Hybrid-engined vehicles are starting to flow onto the market. These vehicles are up to a couple of thousand dollars more expensive than petrol-engined vehicles. Diesel vehicles are, similarly, more expensive than hybrids.

Diesels are well established in Europe and, currently, give similar consumption performance, but they are rare in the USA.

The situation becomes confused because there are all sorts of subsidies and goverment interference in the market of the vehicle, fuel and road-building sectors. For example, the USA is currently giving vast subsidies to heavy SUVs (sports utility vehicles). Smaller subsidies are available in California for hybrids. (This item on fuel consumptions includes links to tax breaks for SUVs and hybrids.)

In the UK, approximately three-quarters of the fuel price is government tax, and diesel prices are maintained at the same level as petrol prices. On the European continent, diesel fuel prices are 20 + % lower than petrol ones, but any fuel saving is heavily offset by considerable tolls on motorways.

It is probable that a diesel or hybrid vehicle will not do more than recover, in fuel savings, the excess expenditure over the vehicle's lifetime.[1] Government priorities tend to be to maximise tax revenue and appeasing their corporate clients, with no great concern for environment and efficiency.

It is necessary to keep in mind that hybrid cars are more complicated and require heavy battery packs. Part of any assessment of a vehicle’s ecology credentials would have to include the energy and materials involved in its production. It is important to realise that lowering the weight of a vehicle also lowers the required size of the engine. This lowers the car’s weight still further—a virtuous feedback. Because hybrids can use their electric motors to assist immediate acceleration, the main drive unit may be smaller.

Hybrids have the potential to generate less pollution; as also do diesels just by virtue of their lower fuel consumption. While there are particulate concerns with diesel, modern diesel engines and fuels are reducing these problems considerably.

dodge city – is the USA quite mad?

the public relations message from DaimlerChrysler

“ [...] our vehicles today, for example, have innovative technologies for reduced fuel consumption and emission levels and they do distinctly reduce pollutant exhaust caused by road traffic.”
—
“ Greater savings through smaller engines
[..] the new 4-cylinder engine saves up to one-fifth on fuel [..] especially when the cubic capacity of the engine is reduced. ”
—
“ [..] DaimlerChrysler will ensure mobility in the future, too, with its conservational approach towards resources. The corporation will continue to play a leading role in this process both with the development of engines consuming less fuel and generating fewer emissions [..] ”

the reality

“Going on sale this fall the trucks include a four-door version of the Dodge Ram SRT-10 pickup, complete with a 500-horsepower [8.3-liter] V-10 engine.

“The regular cab version of the SRT-10 has already given Chrysler bragging rights for brute force. In February it earned a spot in the Guinness Book of World Records as the fastest production pickup truck ever, with a measured top speed of nearly 155 miles per hour.”

The letters SRT stand for Street and Racing Technology.

This is how DiamlerChrysler introduces their new model:

“No one else sports a class-obliterating 500 horsepower and 525 lb.-ft. of torque. And none of those "toy" trucks can even think about topping 150 mph or reaching 60 mph in just over 5 seconds.”

Fuel consumption tests are performed in the USA by the Environmental Protection Agency (EPA) [2]. Typically, such tests are negociated between government and major interests like the oil and vehicle lobbies.You will notice that these fuel consumption tests are deliberately designed to minimise and underplay fuel consumption in normal driving. The official line is that the tests are meant only to be used for comparing different vehicle consumptions. There is no mention of 70 mph highway/motorway driving or any other high fuel consumption activity, let alone going at 155 mph in a truck. For this last, the observer would wonder how many gallons to the mile was being burnt up.
[There is a US government information gold-mine, a FAQ page on understanding fuel ratings and giving good advice concerning fuel consumption.]

“ [...] a long-time customer come in with her new car, complaining about her gas mileage. It was a 2000 model year car with about 9000 miles on it. She said that the window sticker said the gas mileage was 27 miles per gallon in the city and 34 on the highway. She said that the best she ever got with it was 19 mpg.”

As you will see, here is an ordinary driver ending up with two-thirds, going on a half, the number of miles per gallon that the EPA figures would have led them to believe. Put this ludicrous Dodge truck into the hands of the sort of boy racer who would crave such a vehicle and you might wonder what chance of driving five miles to a US gallon. So much for DaimlerChrysler’s “conservational approach towards resources”.

end notes

1. By discounted cashflow, recovering your money over the life of a vehicle is a very bad, economic deal compared with saving the money right now. Thus the hybrid cars are, as yet, at the stage of a rich man’s toy for early adopters but perhaps this will improve over time.
   
   
2. “ Fuel economy estimates are generated from data taken during a laboratory test using pre-production prototype vehicles under extremely controlled conditions using a professional driver, with the vehicle operating on an instrument similar to a treadmill.”
   —
   “The EPA Gas Mileage Guide also points out that the city fuel economy estimate simulates a 7.5 mile stop-and-go trip with an average speed of 20 mph. The trip takes 23 minutes and has 18 stops. About 18 percent of the time is spent idling, as in waiting at traffic lights or in rush hour traffic. Two kinds of engine starts are used: the cold start, which is similar to starting a car in the morning after it has been parked all night, and the hot start, similar to restarting a vehicle after it has been warmed up, driven and stopped for a short time.

   “The test to determine the highway fuel economy estimate represents a mixture of "non-city" driving. Segments corresponding to different kinds of rural roads and interstate highways are included. The test simulates a 10-mile trip and averages 48 mph. The test is run from a hot start and has little idling time and no stops.

   “The EPA Gas Mileage Guide explains that the actual test results are adjusted downward to arrive at the estimates used in the booklet and on the labels. City estimates are lowered by 10 percent and the highway estimate by 22 percent from the laboratory test results.”

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