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An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating by raising the temperature and pressure at which auto-ignition occurs.
The fuel-air charge is meant to be ignited by the spark plug only, and at a precise point in the piston's stroke. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. In a simple explanation, the forward moving wave of combustion that burns the hydrocarbon + oxygen mixture inside ...
Sign on an antique gasoline pump advertising tetra-ethyl lead. Ethyl owned several patents on tetra-ethyl lead, an anti-knock fuel additive, and on its utilization: two patents on the chemical itself, a patent on a motor fuel—gasoline containing tetra-ethyl lead, and a patent on a method of using the fuel in an automobile engine.
In spark-ignition internal combustion engines, knocking (also knock, detonation, spark knock, pinging or pinking) occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but when one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.
Fuel additives in the United States are regulated under section 211 of the Clean Air Act (as amended in January 1995). The Environmental Protection Agency (EPA) requires the registration of all fuel additives which are commercially distributed for use in highway motor vehicles in the United States, [8] and may require testing and ban harmful additives.
The first number indicates the octane rating of the fuel tested to "aviation lean" standards, which is similar to the anti-knock index or "pump rating" given to automotive gasoline in the US. The second number indicates the octane rating of the fuel tested to the " aviation rich " standard, which tries to simulate a supercharged condition with ...
Heptane or n-heptane is the straight-chain alkane with the chemical formula H 3 C(CH 2) 5 CH 3 or C 7 H 16.When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 point is 100% iso-octane).
Tetraethyllead (commonly styled tetraethyl lead), abbreviated TEL, is an organolead compound with the formula Pb(C 2 H 5) 4.It was widely used as a fuel additive for much of the 20th century, first being mixed with gasoline beginning in the 1920s.