ENGINE COMBUSTION CHAMBER

摘要

PROBLEM TO BE SOLVED: To make ignition easier by preventing the concentration of mixed air surrounding an ignition plug from being lean due to weak squish flow on the side opposite to the plug. SOLUTION: A cavity 2 is provided on the side facing a piston 11 of a cylinder head 1. An inlet valve opening 3, an exhaust valve opening 4 and an ignition plug installation opening 5 are provided inside this cavity 2 viewed in a direction parallel to a cylinder central axis 9. Each of these openings are positioned respectively in 3 directions surrounding the central part of the cavity 2 and a squish plane 7 on the side opposite to the plug is formed at the position separated from the ignition plug installation opening 5 by a valve opening portion 6. In a engine combustion chamber, a squish plane 8 on the plug side is formed at the position separated from the squish plane 7 on the side opposite to the plug by the valve opening portion 6 and the ignition plug installation opening 5. A width 8a in a radial direction of the squish plane 8 on the plug side is formed to be smaller than a width 7a in a radial direction of the squish plane 7 on the side opposite to the plug.