To form homogeneous air fuel mixture good for ignition timing in a cylinder by suitably intensifying a tumble flow by fuel injection even in high speed engine operation, in a cylinder injection type spark ignition internal combustion engine intensifying the tumble flow by fuel injected toward an exhaust port side lower part of a cylinder bore or an exhaust port side circumference part of a piston top surface from a fuel injection valve arranged substantially in the center of a cylinder upper part in a vicinity of the intake bottom dead center.
As shown by dotted line, fuel injection rate per unit crank angle is increased as compared to that in engine low speed operation during which same quantity of fuel is injected, and injection start crank angle is not advanced and injection completion crank angle is advanced , in engine high speed operation.
Jun Tsuruta
Tetsuro Shimada
Shinji Mitsuhashi