What Software Taught Me about Gasoline

Friday, May 26, 2006

Years ago, I wrote embedded firmware for 8-bit devices. One set of portable devices could calculate the octane rating of a gasoline sample by measuring the sample’s absorption of near-infrared light*, and are still in production today. Agencies could use the device to make sure gasoline stations were selling gas with the octane ratings they advertised. In the U.S., gas stations typically sell at least two grades of petrol: regular and supreme. Supreme commands a 10 to 15 percent price premium. Regular gas is around 87 PON**, and premium is about 91 PON.

During that time, I learned that buying gas with a higher octane rating than my car requires has absolutely no benefit. Higher-octane gas doesn’t improve gas mileage or horsepower. The octane rating measures a gasoline’s ability to resist premature detonation in the combustion chamber. Premature detonation leads to knocking and pinging sounds in the engine, and is bad because the resulting explosion hammers on the engine’s pistons and leads to damage***.

If my engine isn’t knocking, I stick with the cheaper gas and lower octane ratings (as long as I'm meeting manufacturer’s recommendations).

 

* Only special Cooperative Fuels Research (CFR) engines can produce an official octane reading.

** U.S. pumps display a Pump Octane Number (PON), which is the average of the gasoline’s Research Octane Number (RON) and Motor Octane Number (MON). PON = (RON + MON) / 2. RON measures the gasoline's anti-knock performance under mild operating conditions, while MON measures under harsher conditions (higher RPMs, for instance).

*** Car manufacturers in the early 1900s were trying to build higher compression engines with more power, but premature detonation was destroying the engines. They solved this problem in the 1920s by adding tetraethyl lead to gasoline. Lead is poisonous, of course, but it did boost octane ratings so we forged ahead. The U.S. banned lead additives in 1988. One of lead’s replacements, methyl tertiary butyl ether (MTBE), also boosts octane ratings and as a bonus, lowers emissions. Unfortunately, MTBE is carcinogenic and highly water-soluble. Many states have banned the use of MTBE.


Comments
Sahil Malik Friday, May 26, 2006
"If my engine isn’t knocking, I stick with the cheaper gas and lower octane ratings (as long as I'm meeting manufacturer’s recommendations). "

... I get it, so what you're trying to say is .. if you haven't gotten hacked yet, don't worry about security i.e. stick with cheaper insecure solutions.
scott Friday, May 26, 2006
I think the difference is that if my car isn't pinging today, there is no reason for it to ping in the future (unless I make mods or otherwise change something in the engine).
Ashley Patterson Thursday, July 20, 2006
Ethanol has not been able to replace MTBE. And I strongly feel it won't be able to. Coz MTBE is cheaper and its availability is greater than ethanol. Your estimates have added to the fear!!!
The people have to know the reason behind the price rise instead of blankly supporting the plaintiff lawyers for MTBE LITIGATION against the oil companies. How is that they are they only ones responsible for the use of MTBE? How about the role of the federal government in mandating the use of MTBE as substitute for Tetra -ethyl lead? MTBE did what it was supposed to. And the causing of health problems by MTBE has not yet been confirmed by actual incidents.
Anyone out there interested in being a good citizen and wanting to have knowledge on MTBE?
Do visit the site www.mtbelitigationinfo.com
Jean Claude Thursday, July 20, 2006
Those who don’t know anything about MTBE, go check out the site http://www.mtbelitigationinfo.com and gather some info on MTBE.

GET back to my blog http://mtbe.theblog.cc.

We’ll discuss on anything and everything related to MTBE
Comments are now closed.
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