Premixed Compression Ignition of Formaldehyde-Doped Lean Butane/Air Mixtures in a Wide Range of Temperature

Formaldehyde artificially added into hydrocarbon/air mixtures is efficacious as an ignition control medium for the piston engines. The vapor added into the mixtures gives the premixed compression-ignition (HCCI) engine a stable ignition timing. It allows us to get the MBT controllable by the amount of formaldehyde to be added. The added formaldehyde could be a sole controlling factor to the ignition timing. Depending on the temperature to which mixtures are compressed, the effect of formaldehyde adulteration is either suppressing or promoting. The effect of formaldehyde addition is suppressing on the ignition events belonging originally to the cool-flame dominant ignition. In the preflame induction period of cool-flame dominant ignition the added formaldehyde is superfluous to the cool-flame generating processes. As contrasted with this cool-flame-rich ignition, the formaldehyde effect is promoting on the ignition events belonging the blue-flame dominant regime, where preflame reactions are under the poor cool-flame generating conditions. The efficacy of formaldehyde has been confirmed as an ignition control medium on the piston-compression ignition of hydrocarbon/air mixtures.