Improved piston for an ALCO series 251 diesel engine

摘要

A piston cap for a composite piston of a medium size internal combustion diesel engine, said piston being of the shape of a shallow cylinder, having a diameter of about 9 inches and a sidewall depth of about 3.5 inches, said piston cap having a top surface composed a bowl shaped depression (128) located symmetrically with the centre (134) of the piston cap surrounded by a narrow, flat annual outer surface (118) extending from said depression to the sidewall of said piston cap, a recess formed in the bottom surface of the piston cap extending upwardly toward the top surface so that said piston cap is essentially hollow, the upper surface of said recess which is located somewhat below said top surface and having a pair of circular concentric grooves formed therein, an outer groove (136) having a complex shape and rising to a distance of about 2.8 inches above the bottom surface of said cap and an inner groove (138) spaced from the outer groove by a narrow annular shaped flat land (140), said inner groove rising about 2.7 inches above the bottom surface of said cap and a shaft (144) formed integrally in the upper surface of the centre of said recess which extends downwardly a predetermined distance from said upper surface. IMAGE