Combustion Process. The normal combustion process in the combustion chamber (shown in red in fig. 57) goes through three stages that might be termed formation of nucleus of flame, hatching out, and propagation. Coach Outlet GHD Formation of nucleus of flame. As soon as a spark jumps the gap of the sparkplug electrodes, a small ball of blue flame develops in the gap. This ball is the first stage, or nucleus of flame. It enlarges with relative slowness and, during its growth, there is no measurable pressure created by heat. Hatching-out. GHD Straighteners As the nucleus enlarges, it develops into the hatching-out stage. The nucleus is torn apart so that it sends fingers of flame into the mixture in the combustion chamber. This causes enough heat to give just a slight rise in temperature and pressure in the entire fuel-air mixture. Consequently, a lag still exists in the attempt to raise pressure in the entire cylinder. Propagation. GHD Hair Straighteners It is during the third, or propagation, stage that effective burning occurs. The flame now burns in a “front” which sweeps across the combustion chamber, burning rapidly and causing great heat with an accompanying rise in pressure. MBT GHD
This pressure causes the piston to move downward. MBT Shoes The burning during normal combustion is progressive. It increases gradually during the first two stages, but, during the third stage, the flame is extremely strong as it sweeps through the combustion chamber. Skechers Shape Ups However, there is no violentor explosive action such as when detonation, ordinarily responsible for pinging, or knocking, occurs. Detonation If detonation takes place, it occurs during the third stage of combustion. GHD Hair Straightener The first two stages of burning are normal; but in the propagation stage, flame sweeps from the area around the spark plug toward the walls of the combustion chamber. Hair Straighteners Parts of the chamber that the flame has passed contain inert nonburnable gases, but the section not yet touched by the flame contains highly compressed heated combustible gases.
