Fuel and Additive Characterization for HCCI Combustion

This paper shows a numerical evaluation of fuels and additives for HCCl combustion. First, a long list of candidate HCCl fuels is selected. For all the fuels in the list, operating conditions (compression ratio, equivalence ratio and intake temperature) are determined that result in optimum performance under typical operation for a heavy-duty engine. Fuels are also characterized by presenting Log(p)-Log(T) maps for multiple fuels under HCCl conditions. Log(p)-Log(T) maps illustrate important processes during HCCl engine operation, including compression, low temperature heat release and ignition. Log(p)-Log(T) diagrams can be used for visualizing these processes and can be used as a tool for detailed analysis of HCCl combustion. The paper also includes a ranking of many potential additives. Experiments and analyses have indicated that small amounts (a few parts per million) of secondary fuels (additives) may considerably affect HCCl combustion and may play a significant role in controlling HCCl combustion. Additives are ranked according to their capability to advance HCCl ignition. The best additives are listed and an explanation of their effect on HCCl combustion is included.