How is octane measured?
How is octane measured?
The octane number is determined by comparing, under standard conditions, the knock intensity of the fuel with that of blends of two reference fuels: iso-octane, which resists knocking, and heptane, which knocks readily.
What is octane used for?
The higher the octane number, the more resistant the gasoline mixture is to knock. The use of higher octane fuels also enables higher compression ratios, turbocharging, and downsizing/downspeeding—all of which enable greater engine efficiencies and higher performance.
What is the octane rating scale?
An octane rating is a scale to show you the knock resistance of a given quantity of fuel. Knock resistance relates to the amount of compression the the fuel can take before it ignites. The greater the compression allowed then the greater the knock resistance, and a higher octane rating is earned.
What are the 3 octane levels?
Retail gasoline stations in the United States sell three main grades of gasoline based on the octane level:
- Regular (the lowest octane fuel–generally 87)
- Midgrade (the middle range octane fuel–generally 89–90)
- Premium (the highest octane fuel–generally 91–94)
How do you test octane in fuel?
The Motor Octane Number calculates knock resistance by testing fuel in an engine running at 900 revolutions per minute (rpm). Tests must be run using a standardised engine under controlled conditions. Fuel is preheated to improve accuracy and extra stress is applied through variable ignition timing.
Who discovered octane?
Octane was found with the discovery of crude oil by Edwin L. Drake in August, 1859. He was the first to drill for oil. The octane rating was developed in 1927 by Graham Edgar.
Why is it called octane number?
The name “octane” comes from the following fact: When you take crude oil and “crack” it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels.
Why is higher octane better?
The main difference with premium is its octane rating — 91 or higher compared with 87 for regular octane. The higher octane gives premium gas greater resistance to early fuel ignition, which can result in potential damage, sometimes accompanied by audible engine knocking or pinging.
What are the properties of octane?
Below is a table of some of the basic properties of octane….Properties.
| Formula | C8H18 |
|---|---|
| Molar mass | 114.23 grams/mole |
| Energy density | 47.9 MJ/kg |
| Melting Point | -57oC |
| Boiling Point | 125oC |
Where is octane from?
Where does octane come from? It is one of thousands of different molecules found in crude oil, including alkanes, alkenes and many others. Another name for crude oil is petroleum, which is not the same as petrol. Crude oil originated in marine organic matter like plankton, present millions of years ago in warm seas.
Can higher octane hurt engine?
The higher octane gives premium gas greater resistance to early fuel ignition, which can result in potential damage, sometimes accompanied by audible engine knocking or pinging.
