Ad
related to: engine carbon buildup vs gas octane levels
Search results
Results from the WOW.Com Content Network
Using gasoline of a higher octane than an engine is designed for cannot increase its power output. Octane became well known in American popular culture in the 1960s, when gasoline companies boasted of "high octane" levels in their gasoline advertisements. The compound adjective "high-octane", meaning powerful or dynamic, is recorded in a ...
As South Africa's largest city, Johannesburg, is located on the Highveld at 1,753 meters (5,751 ft) above sea level, the Automobile Association of South Africa recommends 95-octane gasoline at low altitude and 93-octane for use in Johannesburg because "The higher the altitude the lower the air pressure, and the lower the need for a high octane ...
In the United States and Canada, octane ratings are in AKI, commonly shown as "(R+M)/2". All states require gas pumps to be labeled with the correct octane level and nearly all states do regular testing to make sure gas stations are in compliance. A minimum 82 octane fuel is recommended for most vehicles produced since 1984.
A gasoline engine burns a mix of gasoline and air, consisting of a range of about twelve to eighteen parts (by weight) of air to one part of fuel (by weight). A mixture with a 14.7:1 air/fuel ratio is stoichiometric, that is when burned, 100% of the fuel and the oxygen are consumed.
The amount of carbon dioxide emitted per liter or gallon burned varies by fuel type, since each type of fuel contains a different amount of carbon per gallon or liter. The ratings reflect carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 ) emissions, weighted to reflect each gas's relative contribution to the greenhouse effect .
(This is given by the change in Gibbs free energy, and is around 45.7 MJ/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the specific fuel consumption) depends on the engine. A figure of 17.6 MJ/kg is possible with a gasoline engine, and 19.1 MJ/kg for a diesel engine.
Carbon deposits form a heat barrier and can be a contributing factor to pre-ignition. Other causes include: An overheated spark plug (too hot a heat range for the application). Glowing carbon deposits on a hot exhaust valve (which may mean the valve is running too hot because of poor seating, a weak valve spring or insufficient valve lash)
Octane has many structural isomers that differ by the location of branching in the carbon chain. One of these isomers, 2,2,4-trimethylpentane (commonly called iso-octane), is used as one of the standard values in the octane rating scale. Octane is a component of gasoline and petroleum.
Ad
related to: engine carbon buildup vs gas octane levels