Visualization of turbulent flame propagation in a spark ignilion engine operating at 1.200 Images represent g planar slice through the combustion chamber with sequence slarling soon after ignition(upper left photo) and proceeding Until flame comes cylinder walls The flame structure in these photos is in the 'wrinkled laminar flame regime' Speeding up the engine to 2.400 RpM would produce a flame with pockets, or islands' of burned and unburned gases, which is given the structural name "Flamelets in eddies regime'