200 is near top dead center subsequent combustion when the piston is on its down stroke allows efficient removal of unburned hydrocarbons in this region of the chamber the combustion chamber 215 creates efficient removal of unburned hydrocarbons from portion 232 because portion 232 is a significant fraction of the overall squish area portion 232 plus portion 237 thus overall emissions of unburned hydrocarbons from the combustion chamber 215 will be lower than those of a conventional combustion chamber by controlling the peak pressure and temperature used in high bmep applications advanced ignition timing can be utilized thus the life of the ignition plug 260 can be extended high bmep applications produce relatively high temperature and pressure in the combustion chamber 215 because the peak temperature and pressure can be controlled through the current chamber designs the plug 260 can be ignited at a lower pressure advanced ignition timing than in conventional combustion chambers because the ignition plug 260 can be fired at lower pressure the plug has a longer life span the ignition plug 260 described herein can be any ignition plug that is capable of igniting the mixture the secondary chamber 235 is ignited as the flames from the primary combustion event travel across the inner annular raised portion 232 the flames will combust the remaining mixture in the secondary chamber 235 by providing the secondary chamber 235 with a predetermined volume of mixture again the peak temperature and pressure in the combustion chamber 215 can be controlled by providing another chamber wall 239 and the outer annular raised portion 237 the flame propagation speed can again be controlled and decrease the potential for knock the flame propagation speed is slowed because the flame must travel up the wall 239 of the secondary chamber.