Glow-plug assisted cold start of premixed compression-ignition natural-gas engines

A glow-plug assisted procedure is examined herewith to try to establish easy start and warm-up processes of the premixed-compression-ignition (i.e. homogeneous charge compression ignition, HCCI) natural-gas engines easy. A confirmation experiment is shown using a single cylinder engine and the natural gas/air mixture with an equivalence ratio of 0.6. The wall temperature of the combustion chamber was an important controlling factor to obtain the heat release of hot-flame explosion for the engine starting and warming, even though the glow plug would assist the ignition process of the mixture. It is necessary to get blue-flame dominant charge temperature, 850 K, near the top dead center by the piston compression of the mixture to establish self-sustaining engine operations. A glow plug installation will raise the local mixture temperature, which will result in the higher local temperature of compressed mixture. The formaldehyde addition into the charge makes it easy to obtain the hot-flame ignition during the starting and warming.