The present invention relates to a multi-piece, in particular at least two-piece, piston (1) for an internal combustion engine having a longitudinal axis (L), comprising a piston outer part (10) having a closed piston head (11), which in the fitted state defines a combustion chamber, and a piston body (13) extending axially away from the piston head (11), and a piston inner part (20), which in the fitted state is connected to a connecting rod. An outer surface (2) radially defining the piston (1) is formed exclusively by at least one portion of the piston body (13) of the piston outer part (10). The piston inner part (20), viewed in an axial direction, is arranged radially entirely inside the piston body (13) or its circumferential surface.

Improving an IC Engine’s thermal efficiency by heat preservation by providing: heat insulation layers to the cylinder, piston crown, combustion chamber and cylinder-head including internal gaps/cavities with or without vacuum; reduced carbonisation of fuel and oil; reduced the thermal shock by exhaust gas recirculation - EGR with control/intake valves, heating and storage tank; improved thermal shock resistance of insulation with flexible/porous thread/fibre and cloth materials bound together by binding with paste, stitching, weaving, braiding or pressed/clamped together; improved distortion resistance using sapphire or tungsten steel; an elongated piston cap or cone; segmented or annular sheet cylinder/liner construction; direct or indirect cooling of fuel injectors with fuel recirculation or spark plugs with high pressure gas jets in pits or slits.

The present invention relates to a multi-piece, in particular at least two-piece, piston (1) for an internal combustion engine having a longitudinal axis (L), comprising a piston outer part (10) having a closed piston head (11), which in the fitted state defines a combustion chamber, and a piston body (13) extending axially away from the piston head (11), and a piston inner part (20), which in the fitted state is connected to a connecting rod. An outer surface (2) radially defining the piston (1) is formed exclusively by at least one portion of the piston body (13) of the piston outer part (10). The piston inner part (20), viewed in an axial direction, is arranged radially entirely inside the piston body (13) or its circumferential surface.