Piston for internal combustion engine with direct fuel injection

Claim 1

A piston for direct injection internal combustion engines having a pistonhead portion and having a wrist pin yoke and slipper means forming a lower piston section, said pistonhead portion comprising a hollow cylindrical element provided with piston ring grooves forming a short piston skirt, a combustion chamber insert formed with a peripheral flange welded to the said hollow cylindrical element to close the top of said piston, said combustion chamber insert being also provided at a point remote from said peripheral flange with cylindrical boss having its axis concentric with said short piston skirt and a casing sealed at the top to said peripheral flange of said combustion chamber and sealed at the bottom to saiD hollow cylindrical boss, said casing being spaced from the wall of said combustion chamber to form a space to receive a cooling medium, and a space between said casing and said short piston skirt, said lower piston section comprising a yoke element carrying wrist pin bushings and having a boss thereon complementary to said cylindrical boss on said combustion chamber insert and welded thereto to hold said lower piston section and said pistonhead portion in axial alignment, said slipper means being secured to said yoke to support the lateral thrust of said piston against the cylinder walls of an engine when in use.