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The cetane number of a fuel is defined by finding a blend of cetane and isocetane with the same ignition delay. Cetane has a cetane number defined to be 100, while isocetane's measured cetane number is 15, replacing the former reference fuel alpha-methylnaphthalene, which was assigned a cetane number of 0. Once the blend is known, the cetane ...
Cetane index is used as a substitute for the cetane number of diesel fuel. The cetane index is calculated based on the fuel's density and distillation range (ASTM D86). There are two methods used, ASTM D976 and D4737. The older D976, or "two-variable equation" is outdated and should no longer be used for cetane number estimation.
Petrol additives may increase petrol's octane rating, thus allowing the use of higher compression ratios for greater efficiency and power, or act as corrosion inhibitors or lubricants. Other additives include metal deactivators, oxygenates and antioxidants. Some additives are harmful and are regulated or banned in some countries.
As the treatment with additives (1:40000 [40]) is a cheaper way to enhance No.2 fuel in winter, most stations offer winterized diesel in cold weather conditions. In regions with colder weather, most gas stations offer No.1 fuel at the same pump allowing drivers to decide for themselves on a winter blend. [citation needed]
Hexadecane (also called cetane) is an alkane hydrocarbon with the chemical formula C 16 H 34. Hexadecane consists of a chain of 16 carbon atoms , with three hydrogen atoms bonded to the two end carbon atoms, and two hydrogens bonded to each of the 14 other carbon atoms.
Isocetane (2,2,4,4,6,8,8-heptamethylnonane) is a highly branched alkane used as a reference in determining the cetane number of diesel. It has a cetane number of 15. [ 2 ] Isocetane replaced 1-methylnaphthalene in 1962 as the lower reference for cetane number (1-methylnaphthalene has cetane number zero) owing to the oxidation instability and ...
For spark-ignition engines the fuel has an octane rating. For diesel engines it depends on the type of fuel, for distillate fuels the cetane numbers are used. Cetane numbers are tested using a special test engine, however, the existing test engine was not intended for residual fuels.
The cetane number is a key property of diesel fuel, as it measures its aptitude to self-ignite in the combustion chamber. [8] The auto ignition temperature of diesel fuel is around 220 °C (428 °F) at atmospheric pressure. Cetane improver additives are used to decrease this temperature and lead to quicker combustion, by increasing the cetane ...