RE: Gasolina
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RE: Gasolina - 5/5/2007 12:05:21 PM
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transamlt1man
Posts: 796
Joined: 9/4/2005
Status: offline
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Well here is a few pages of it. If you want to read about ethanol and race fuel I can add the rest. Some source are below if you don't believe me.
Pulling up to the gas pump to fuel up a vehicle is a weekly routine for most people. After getting out of the vehicle there are two or three choices most of the time, unleaded regular gasoline with 87 octane, unleaded plus with 89 octane, and unleaded premium with a whooping 93 octane rating. These octane numbers can be confusing to most vehicle owners. “Octane ratings measure a gasoline’s ability to resist engine knock, a rattling or pinging sound that results from premature ignition of compressed fuel-air mixture in one or more cylinders” (F.T.C. 1). In more understandable words, when a piston is on its compression stroke nearing top dead center, if the fuel has to low of an octane rating for the engine, the gasoline will actually ignite itself before the spark plug ignites it, resulting in a knocking noise. This is known as premature ignition or preignition. Over time engine damage can occur because of premature ignition. This is why octane ratings should not be over looked.
Zooming in on the octane sticker next to the pump, an equation for the octane rating can be found. RON+MON/2= Octane. According to Phil Coconis, “MON is the ability to reduce knocking at high RPM’s and loads, and RON is the ability to reduce knocking at lower RPM’s” (Coconis 1). For example, say an engine can use a minimum octane rating of 85 at high RPM’s and loads, and has a minimum octane rating of 89 at higher RPM’s and load. Adding the two numbers up and dividing by two will give a minimum octane rating of 87. This will be the number on the large yellow sticker next to the pump nozzle.
Most vehicle owners may have wondered if they are using the correct octane fuel. They may think they are abusing their car by only fueling unleaded regular gasoline in their fuel tanks. To understand what fuel must be used in every car there is one simple answer. Open the owner’s manual and find out what is recommended for that vehicle. In every manual it will state what octane fuel should be run. The engineers run multiple tests to figure out the best octane for that specific engine. Upgrading to the next higher fuel octane rating will not harm an engine but it will also have no benefits. The Federal Trade Commission state, “Higher octane gasoline is not better at preventing engine deposits from forming or cleaning the cars engine. All brands of gasoline must contain cleaning detergent additive to protect against carbon build-up” (F.T.C. 1). The higher octane only helps prevent premature ignition and will not keep an engine cleaner.
Octane ratings can be different for all types of engines. There are many factors that play a role on what the minimum octane gasoline is needed. “Compression ratio, ignition timing, air-fuel ratios, temperatures and combustion chamber design all have an affect of the octane number requirement. Compression ratio has the most significant impact on the octane number required and engine efficiency” (Cann 1). When a large volume of air/fuel is compressed into smaller areas, a higher compression ratio will result. “A vast majority of new cars do fine on regular 87 octane” (Peters 35). Which their engine would probably have an 8.5 to 1 compression ratio. Higher compression engine such as 10 to 1 compression will require about 93 premium octane fuel. Over that such as 12 to 1 or even 13.5 to 1 could require even higher octane. Stated by Rick Sieman, “The relationship of compression ratio to the octane rating has no real linear relationship” (Sieman 2). There is no set number of octane for a specific compression ratio. Every engine is different and requires different needs. Basically without the use of a “high-compression, high-performance sports or luxury car, an engine will run just fine on regular unleaded gasoline” (Peters 35).
Although r
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