Patent attributes
To provide an improved swirl forming device in a combustion engine, which is effective to promote a vigorous and massive swirling motion of the charge mixture within the combustion chamber, the swirl forming device includes an auxiliary passage (24) for introducing an auxiliary gas, which may be either air or a charge mixture, into the combustion chamber (9) from a location immediately upstream of the intake port (70) that is selectively opened and closed by the intake valve (10). This auxiliary passage (24) has an open end (25) positioned adjacent the exhaust port (80), such that when viewed from top in a direction conforming to the longitudinal axis (CC) of the cylinder bore (3), the auxiliary gas is introduced in a direction different from the direction (N) normal to the inner peripheral surface (3a) of the cylinder bore (3) to thereby form a swirl (S) along the inner peripheral surface (3a) of the cylinder bore (3).