PURPOSE: To sufficiently stratify fuel by forming recesses offset to the rotation- of-advance side in rotator flanks and specifying the arrangement of a fuel injection valve and the time of fuel injection.
CONSTITUTION: Recesses 9-11 offset to the rotation-of-advance side are formed on rotor flanks 2a-2c of the surface of a rotor 2 in a housing 1. A fuel injection valve 16 is located on the rotation-of-delay side of the first and second spark plugs 14, 15 to define a directional way α as the first spark gap 14a on the advance side. Mist from the fuel injection valve 16 is set to reach the recess 9 later than a time right after an apex seal 4 passes through the first spark gap 14a. The injection is completed while a space (d) between the edge on the delay side of the recess 9 and the inner face of the rotor housing 1 is larger than the mist width (e). In this way, rich mixture is formed at the time of ignition for sufficient stratification.
HASEGAWA YASUAKI
HAMAI YUJI
