Diesel engine and piston assembly therefor.

摘要

An automotive diesel engine is provide with pistons (21) each of which carries two compression rings (25-27) and an oil control ring. The cold end clearance of the lower compression ring (27) is at least three times greater than the cold end clearance of the top compression ring (25). The annulus defined by the second land (32) of the piston (21), the two compression rings (25-27) and the engine cylinder wall (11) has an empirically determined volume (35) which is within the range of about 0.12 cubic inches (0.00196 litre) to about 0.35 cubic inches (0.00574 litre). The top land (31) of the piston is set back to provide exaggerated diametral clearance from the cylinder wall.