https://wikicars.org/index.php?action=history&feed=atom&title=Calculated_Ignition_Index 2026-04-22T18:04:50Z Revision history for this page on the wiki MediaWiki 1.38.4 https://wikicars.org/index.php?title=Calculated_Ignition_Index&diff=153737&oldid=prev 2010-05-20T15:59:17Z

<p></p> <p><b>New page</b></p><div>The &#039;&#039;&#039;Calculated Ignition Index&#039;&#039;&#039; (CII) is an index of the ignition quality of residual fuel oil.<br /> <br /> The running of all internal combustion engines is dependent on the ignition quality of the fuel. 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 number]]s are used. Cetane numbers are tested using a special test engine and the existing engine was not made for residual fuels. For residual fuel oil two other empirical indexes are used CII and [[Calculated Carbon Aromaticity Index]] (CCAI). Both CII and CCAI are calculated from the density and kinematic viscosity of the fuel.<br /> <br /> ==Definition==<br /> Formula for CII:<br /> <br /> &lt;math&gt;CII = (270.795 + 0.1038T)-0.254565D+23.708 \log \log(V+0.7)\,&lt;/math&gt;<br /> <br /> Where:&lt;br /&gt;<br /> D = density at 15°C (kg/m³)&lt;br /&gt;<br /> V = viscosity (cST)&lt;br /&gt;<br /> T = viscosity temperature (°C)&lt;br /&gt;<br /> <br /> ==Use==<br /> CII was designed to give out numbers in the same order as the cetane index for distillate fuels.<br /> <br /> [[Category:Combustion]]</div>

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