Staged combustion

Staged combustion is a method for reducing nitrogen oxides (NOx) emissions from combustion. There are two methods - air staged supply and fuel staged supply. Applications include boilers and rocket engines.

Staged combustion dates back to the hot bulb engine of the 1890s. The first stage of combustion occurred inside the hot bulb and the hot gases were then forced out into the cylinder, where they mixed with additional air, and the second stage of combustion took place. At this time, staged combustion was used because it was a convenient method of ignition and it is unlikely that there would have been much concern about air pollution. A modern application of the principle is the Stratified charge engine, in which a rich mixture is ignited by a spark and the resulting flame-front ignites the weaker mixture elsewhere in the cylinder.

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