Internal combustion engines having non-circular, preferably rectangular, cross-section pistons and cylinders are disclosed. 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, and 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.

The invention relates to a piston for an internal combustion engine having two skirt wall (10), which are connected by connecting walls (14), which bear piston-pin bosses, wherein at least one skirt wall (10) has a greater wall thickness in a region (12) that is central along the piston periphery and in the lateral regions than between the central region (12) and each lateral region and is continuously curved on the inside of the piston in a section perpendicular to the piston axis, and wherein the wall thickness distribution is substantially constant in the direction of the piston axis.

An internal combustion engine includes an engine main body defining a cylinder bore, a piston received in the cylinder bore, and a crankshaft rotatably supported by the engine main body and connected with the piston via a connecting rod, the piston including a skirt. The cylinder bore includes a first region defined as a range along the cylinder axial line on a side of a top dead center from a first piston position, and a second region defined as a range along the cylinder axial line on a side of the bottom dead center from a second piston position closer to the bottom dead center than the first piston position, and a connection region positioned between the first and second regions. A diameter of the cylinder bore is smaller in the first region than in the second region, and the connection region connects the first and second regions smoothly.

A piston of an internal combustion engine having a piston head which has a ring zone and is adjoined by a piston skirt which encloses an inner shape, with two box walls which lie opposite one another and are set back with respect to the outer contour of the piston and with two skirt walls which are not set back with respect to the outer contour of the piston, wherein the box walls receive hubs, wherein the piston skirt has skirt supports which are connected to the hub, wherein the width of the box wall is a point of intersection between the pin axis and the constant-curvature and constant-tangent further course of the box wall, and to a method for producing a piston for internal combustion engines.

A piston for an internal combustion engine may include two pin bosses configured to receive a gudgeon pin. The two pin bosses may respectively include a nadir pocket of at least two nadir pockets at =180 and extending outward from a piston axis. The at least two nadir pockets may have a respective length that is smaller than a length of a respective pin boss of the at least two pin bosses. The piston may also include a pin boss axis that is axially offset from the piston axis by 0.1-1.0 mm.

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.

Internal combustion engines having non-circular, preferably rectangular, cross-section pistons and cylinders are disclosed. 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, and 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.

Internal combustion engines having multi-stage telescoping poppet valves in lieu of conventional poppet valves are disclosed. The engines may have pistons with a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston heads may include one or more depressions and may be domed to 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 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.

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 that use the pumping motion of the engine pistons to supercharge the cylinder with air/charge are disclosed. The pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston heads may be domed with one or more depressions to facilitate the movement of air/charge in the cylinder. The engines also may 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 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.