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We get snowed when it comes to explaining the resons for the hikes in the cost of gasoline, but has anyone noticed the cost added for premium grades?
A reason offered for the high cost of gasoline is a shortage of refineries. The additive is not a refined product, but it has escalated along with the fuel in lockstep. The actual amount added per gallon to remove the engine knock in high compression engines less the 1 cc.
RRRRip!
News report says Saudis have raised their local countries gas pump prices to $0.11 cents a litre. Wow! Canada as the single largest exporter of oil to the USA, why do we pay $1.30 a litre here and by simply crossing the border to Bellingham USA we could be paying the equivilent of $0.85 cents. We should have two tiered pricing in Canada too. At absolute minumum we should have cheaper gas than the US especially as their largest exporter of oil!
Stand up and say you won't take it anymore. Visit http://www.cknw.com/shows/
show_w..._worldToday.cfm and email cknw and email the petition, http://www.cknw.com/station/
gas_...as_petition.pdf
today to our MLAs , M Polak & R. Coleman. Send it to Local MP M. Warawa too while your at it.
Jafo,
not to support the gas companies, but the difference between grades is not due to additives the difference has to do with the octane of the fuel which is a function of the refining process.
My knowledge is weak here, but the additives are ethanol, MBTE, or toluene, and perhaps others(?)
Perhaps Blair, you are aware of the process to produce these additives.
Like Jafo, I am suspicious of why the higher octane fuels cost so much more, when possibly the additives are not more expensive to produce.
Methinks,
To give it to you in the simplest terms there are three different primary components in fuels that end up in our gas tanks. The raw fuel, additives to enhance the combustion process and additives for cleaning fuel systems. Lets discuss each in reverse order.
The cleaning additives (techron etc...) are solvents mixes (stoddart solvents etc..) in combination with some form of anti-sticking agent (teflon or some similar polymer). These are added to gas in minute quantities (milliliters per litre) and are designed to prevent or reduce build-up in your engine.
The second component of gas are the additives like MTBE, MMT, TAME and others which are designed to enhance the oxygen content of the fuel in order to cause the fuel to burn more cleanly (combustion calls for oxygen and hydrocarbon and in typical fuels the more oxygen the cleaner the combustion and the less tailpipe emissions). The oxygenates are added to fuels based on regulatory and other conditions (like climate) and can make up a very large proportion of the fuel (in some areas up to 10% - 20% of the fuel can be oxygenate). The more oxygenate you have the less power per liter as the oxygenate cleans the combustion but does not provide power for the burn.
Finally the majority of the fuel is made up of hydrocarbons that have been refined from crude oil. The refined mixture is called automotive gasoline. Gasoline is made up a mix of hydrocarbons of various shapes and sizes that have the approximate carbon numbers of C5 through C16 ish. Some of the major subcomponents in gasoline include benzene, toluene, ethylbenzene, xylenes, octane etc... I added the last one to confuse you a bit because while octane literally means a molecule with eight carbons units there is another thing called “pump octane” The pump octane is a calculated function (to save time I am inserting some text from the Gasoline FAQ here) “to obtain the maximum energy from the gasoline, the compressed fuel-air mixture inside the combustion chamber needs to burn evenly, propagating out from the spark plug until all the fuel is consumed. This would deliver an optimum power stroke. In real life, a series of pre-flame reactions will occur in the unburnt "end gases" in the combustion chamber before the flame front arrives. If these reactions form molecules or species that can autoignite before the flame front arrives, knock will occur. Simply put, the octane rating of the fuel reflects the ability of the unburnt end gases to resist spontaneous autoignition under the engine test conditions used. If autoignition occurs, it results in an extremely rapid pressure rise, as both the desired spark-initiated flame front, and the undesired autoignited end gas flames are expanding. The combined pressure peak arrives slightly ahead of the normal operating pressure peak, leading to a loss of power and eventual overheating. The end gas pressure waves are superimposed on the main pressure wave, leading to a sawtooth pattern of pressure oscillations that create the "knocking"sound”."
Back to me here. To summarize, octane defines how easily the gas burns in the engine and ensures that the combustion goes in one direction (from the spark plug forcing the piston out and thus giving power). Each automobile engine is designed to operate with gasoline with a specific octane. Oddly enough if your car is designed to run an 87 octane fuel buying the better stuff (89, 91) not only doesn’t help your engine it actually reduces your gas mileage. Thus if your car is designed to burn regular, all you are doing when you buy premium is spending more money for gasoline that makes your engine run worse.
If you want more details I will provide it but I hope this helps.
Cheers,
Blair
Ooops I forgot to point out, higher octane gasoline needs more refining since it has a more precise composition. The higher price is supposed to represent the added refining cost to make the more refined product.
Thank you Blair. That was more detailed than I expected. I just hope there is no rip-off in the supposed added refining process.
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