Four-stroke IC engine - has spark ignition in precombustion chamber with defined volume and flame duct geometry

摘要

The four-stroke Otto engine comprises a cylinder with main combustion chamber (4), piston (2), inlet (8) and exhaust valves and a rotationally symmetric pre-combustion chamber (5) with an ignition plug (9) and a duct (6) connecting it with the main chamber. The combined volume of chamber (5) and duct is approximately 7 to 20% of the total compression volume. The cross-section of the duct converges from the chamber (5) at an angle (alpha) of between 0 and 2.5 deg. in the direction of the main chamber. The chamber may have a hemi-spherical shape. The total length (L) of the chamber plus duct is pref. greater than or equal to the smallest dia. (d) of the duct.