A piston for an internal combustion engine, said piston having an upper piston portion (1) in which a ring zone (2) is located, and a piston lower part (3) having two opposing, load-carrying skirt wall sections (4,5) on the pressure- and counter-pressure sides of the piston adjoins the upper piston portion (1), and the two load-carrying skirt wall sections (4,5) are interconnected via connecting walls (6,7) that are recessed relative to the outer diameter of the piston. Each connecting wall (6,7) includes a pin bore having a pin bore axis (18) for receiving a pin. The two opposing, load-carrying wall section (4,5) have different wall thicknesses and different transition regions at the transition of their lateral skirt connections (8,9 and 16,17) to the recessed connection walls (6,7).

A method for producing a piston blank or a piston for an internal combustion engine, includes providing a thickened portion formed in at least one box wall in the direction of thickness approximately in the center thereof, which is at least partly flush with a cooling channel. A resulting piston blank or piston having these features can be made in a casting mold or forging die designed in a corresponding manner.

A method for producing a piston blank or a piston for an internal combustion engine, includes providing a thickened portion formed in at least one box wall in the direction of thickness approximately in the center thereof, which is at least partly flush with a cooling channel. A resulting piston blank or piston having these features can be made in a casting mold or forging die designed in a corresponding manner.

A piston (10) for an internal combustion engine, includes shaft wall sections (18) for supporting in a cylinder or a cylinder liner, and at least one base support (20) that is connected thereto in the circumferential direction, and which has at least one contour that forms a section of a helix.

A piston (10) for an internal combustion engine, includes shaft wall sections (18) for supporting in a cylinder or a cylinder liner, and at least one base support (20) that is connected thereto in the circumferential direction, and which has at least one contour that forms a section of a helix.

Internal combustion engines having a split crankshaft are disclosed. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The pistons also may have a domed piston head with depressions thereon to facilitate the movement of air/charge in the cylinder. The engines also may use multi-stage poppet valves in lieu of conventional poppet valves. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

Internal combustion engines having pistons with one or more depressions located on the piston head to facilitate the movement of air/charge in the cylinder are disclosed. The pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston head also may be domed to further facilitate the movement of air/charge in the cylinder. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The engines also may use multi-stage poppet valves in lieu of conventional poppet valves, and may include a split crankshaft. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

An enhanced piston for improving the efficiency of an internal combustion engine has a cylinder with a combustion chamber and a lower cylinder portion. A cylinder head is disposed on the cylinder. An enhanced piston is moveably disposed within the cylinder and is connected to a piston rod. The enhanced piston has a piston cavity. There is an upper piston valve connected to an upper piston valve rod. The upper piston valve is disposed within the piston cavity wherein the upper piston valve selectively seals said piston cavity from the combustion chamber. A piston cavity port is disposed on a bottom portion of the piston cavity and is selectively opened and closed with a lower piston valve. The lower piston valve seals the piston cavity port from the lower cylinder portion. This way the gases are selectively sealed in the piston cavity under pressure until released in the combustion chamber.

A piston for an internal combustion engine has a plurality of recesses formed in a skirt including an upper, a lower, and a central portion. The recesses in the upper portion close to an upper boundary of the central portion have lower ends located upwardly at a given distance away from the upper boundary. The recesses in the central portion close to the upper boundary have upper ends located downwardly at the given distance away from the upper boundary. The recesses in the lower portion close to the lower boundary have upper ends located downwardly at the given distance away from the lower boundary. The recesses in the central portion closer to the lower boundary have lower ends located upwardly at the given distance away from the lower boundary. This enhances lubrication between the piston and an inner wall of a cylinder bore and reduces a friction loss of the piston.

An enhanced piston for improving the efficiency of an internal combustion engine has a cylinder with a combustion chamber and a lower cylinder portion. A cylinder head is disposed on the cylinder. An enhanced piston is moveably disposed within the cylinder and is connected to a piston rod. The enhanced piston has a piston cavity. There is an upper piston valve connected to an upper piston valve rod. The upper piston valve is disposed within the piston cavity wherein the upper piston valve selectively seals said piston cavity from the combustion chamber. A piston cavity port is disposed on a bottom portion of the piston cavity and is selectively opened and closed with a lower piston valve. The lower piston valve seals the piston cavity port from the lower cylinder portion. This way the gases are selectively sealed in the piston cavity under pressure until released in the combustion chamber.