Patent ID: 8006666

Claim:
An internal combustion engine comprising: a main combustion chamber; an auxiliary combustion chamber having a capacity smaller than that of the main combustion chamber and being fluidly communicated with the main combustion chamber through a torch flame passage formed therebetween; a first igniter disposed in the auxiliary combustion chamber; a second igniter disposed in the main combustion chamber; and a controller electrically coupled to the first and second igniters and configured to determine and control ignition timings of the first and second igniters respectively in response to at least one engine operating condition such that ignition in the auxiliary combustion chamber occurs after ignition in the main combustion chamber, wherein the controller varies a phase angle difference between the ignition in the main combustion chamber and the ignition in the auxiliary combustion chamber in response to an engine condition; wherein the phase angle difference is controlled to be smaller as an engine load decreases.