Premixed compression ignition control for the piston engines

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The low-temperature-ignition classification ; three typical regime, "cool-flame dominant regime, "negative-temperature-coefficient regime" and "blue-flame dominant regime" would be a universal advanced/retarded criterion on ignition of fuel/air mixtures with formaldehyde doping for the ignition timing control in the premixed-compression-ignition engines. The formaldehyde would be a suppressing additive under the cool-flame generating constituents, temperature and pressure conditions, and a promoting additive under the poor cool-flame generating conditions in the cylinder charge during the preflame reactions leading to the ignition. The added formaldehyde is superfluous to the ignition event originally belonging to the cool-flame dominant regime, which would give a suppressing effect. On the other hand, the artificially added formaldehyde could be a starting point of preflame reactions leading to the final hot ignition belonging to the blue-flame-dominant regime, where a few fuel transition and low intermediates appear, and where the high temperature chemistry dominates. It allows a short cut of the preflame induction period, in consequence, a promoting effect for the ignition.A glow-plug assisted procedure is examined for the cold start of the natural-gas premixed-compression-ignition engine engines. A glow plug installation and formaldehyde addition will raise the load mixture temperature, which will result in the higher local temperature of compressed mixture. Spark-ignition operation for temperature increase would be an alternative starting procedure.