Antiknock Agent
Antiknock agent
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 ignition occurs. The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early before the correctly timed spark occurs (pre-ignition ordetonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise.
Research[edit]
Early research into this effect was led by A.H. Gibson and Harry Ricardo in England and Thomas Midgley, Jr. and Thomas Boyd in the United States. The discovery that leadadditives modified this behavior led to the widespread adoption of the practice in the 1920s and therefore more powerful higher compression engines. The most popular additive was tetraethyllead. However, with the discovery of the environmental and health damage caused by the lead, and the incompatibility of lead with catalytic converters found on virtually all US automobiles since 1975, this practice began to wane in the 1980s. Most countries are phasing out leaded fuel although different additives still contain lead compounds. Other additives include aromatic hydrocarbons, ethers and alcohol (usually ethanol or methanol).
Typical agents[edit]
'The typical antiknock agents in use are:
Tetraethyllead (Still in use as a high octane additive)
Methylcyclopentadienyl manganese tricarbonyl (MMT)
Ferrocene
Iron pentacarbonyl
Toluene
Isooctane
Tetraethyllead[edit]
A side effect of the lead additives was protection of the valve seats from erosion. Many classic cars' engines have needed modification to use lead-free fuels since leaded fuels became unavailable. However, "Lead substitute" products are also produced and can sometimes be found at auto parts stores.
Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve combustion, and to allow easier starting in cold climates.
MMT[edit]
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 ignition occurs. The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early before the correctly timed spark occurs (pre-ignition ordetonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise.
Research[edit]
Early research into this effect was led by A.H. Gibson and Harry Ricardo in England and Thomas Midgley, Jr. and Thomas Boyd in the United States. The discovery that leadadditives modified this behavior led to the widespread adoption of the practice in the 1920s and therefore more powerful higher compression engines. The most popular additive was tetraethyllead. However, with the discovery of the environmental and health damage caused by the lead, and the incompatibility of lead with catalytic converters found on virtually all US automobiles since 1975, this practice began to wane in the 1980s. Most countries are phasing out leaded fuel although different additives still contain lead compounds. Other additives include aromatic hydrocarbons, ethers and alcohol (usually ethanol or methanol).
Typical agents[edit]
'The typical antiknock agents in use are:
Tetraethyllead (Still in use as a high octane additive)
Methylcyclopentadienyl manganese tricarbonyl (MMT)
Ferrocene
Iron pentacarbonyl
Toluene
Isooctane
Tetraethyllead[edit]
A side effect of the lead additives was protection of the valve seats from erosion. Many classic cars' engines have needed modification to use lead-free fuels since leaded fuels became unavailable. However, "Lead substitute" products are also produced and can sometimes be found at auto parts stores.
Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve combustion, and to allow easier starting in cold climates.
MMT[edit]