A steel piston with an engineered coating is provided. A high thermal conductivity material, for example copper, is disposed on first regions of a combustion bowl to reduce hot spots in the piston. A low thermal conductivity material, for example a ceramic, is disposed on second regions of the combustion bowl to reduce loss of heat through the piston. The high thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 5 μm to help reflect IR radiation and promote fuel flow. The low thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 3 μm to promote fuel flow. The low thermal conductivity material is also disposed on the bowl rim and top ring land, and has a surface roughness (R.sub.a) of greater than 8 μm on the bowl rim and top ring land to retard gas flow.

A steel piston with an engineered coating is provided. A high thermal conductivity material, for example copper, is disposed on first regions of a combustion bowl to reduce hot spots in the piston. A low thermal conductivity material, for example a ceramic, is disposed on second regions of the combustion bowl to reduce loss of heat through the piston. The high thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 5 μm to help reflect IR radiation and promote fuel flow. The low thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 3 μm to promote fuel flow. The low thermal conductivity material is also disposed on the bowl rim and top ring land, and has a surface roughness (R.sub.a) of greater than 8 μm on the bowl rim and top ring land to retard gas flow.

A piston may have an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, a plane containing the longitudinal axis and the radial direction, and a contoured combustion bowl. In the plane containing the longitudinal axis and the radial direction, the crown portion includes a radially outer squish surface, and a swirl pocket having a reentrant surface that extends axially downwardly and radially outwardly from the squish surface defining a tangent that forms a reentrant angle with the squish surface that ranges from 33.0 degrees to 37.0 degrees.

A piston may have an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, a plane containing the longitudinal axis and the radial direction, and a contoured combustion bowl. In the plane containing the longitudinal axis and the radial direction, the crown portion includes a radially outer squish surface, and a swirl pocket having a reentrant surface that extends axially downwardly and radially outwardly from the squish surface defining a tangent that forms a reentrant angle with the squish surface that ranges from 33.0 degrees to 37.0 degrees.

A piston assembly includes a piston head for reciprocating back and forth within a cylinder of an engine, an upper rod coupled to the piston head at one longitudinal end of the upper rod and fixed relative to the piston head, and a lower rod rotatably coupled to an opposite longitudinal end of the upper rod, the lower rod configured to pivot about the opposite longitudinal end of the upper rod. The lower rod is configured to couple to a crankshaft at a longitudinal end of the lower rod opposite the upper rod. Methods of forming a piston assembly and engines incorporating such piston assemblies are also disclosed.

A piston assembly includes a piston head for reciprocating back and forth within a cylinder of an engine, an upper rod coupled to the piston head at one longitudinal end of the upper rod and fixed relative to the piston head, and a lower rod rotatably coupled to an opposite longitudinal end of the upper rod, the lower rod configured to pivot about the opposite longitudinal end of the upper rod. The lower rod is configured to couple to a crankshaft at a longitudinal end of the lower rod opposite the upper rod. Methods of forming a piston assembly and engines incorporating such piston assemblies are also disclosed.

The present invention allows the air-fuel mixture to swirl in a combustion chamber to increase the power from the engine. Each engine cylinder contains a piston, a combustion chamber, and at least one intake valve, exhaust valve, and spark-plug. Also, the top of the piston head contains a hole that forms the entry point of a converging nozzle, where the air-fuel mixture is first directed downwards and then horizontally through intake nozzles onto ramps located on the inner walls of the combustion chamber that allows the air-fuel mixture to swirl in a counter-clock wise motion. This swirling effect causes a cyclone inside the combustion chamber that when ignited it results in an additional explosive force that drives the piston downwards with additional acceleration, which increase the power produced by the engine.

The present invention allows the air-fuel mixture to swirl in a combustion chamber to increase the power from the engine. Each engine cylinder contains a piston, a combustion chamber, and at least one intake valve, exhaust valve, and spark-plug. Also, the top of the piston head contains a hole that forms the entry point of a converging nozzle, where the air-fuel mixture is first directed downwards and then horizontally through intake nozzles onto ramps located on the inner walls of the combustion chamber that allows the air-fuel mixture to swirl in a counter-clock wise motion. This swirling effect causes a cyclone inside the combustion chamber that when ignited it results in an additional explosive force that drives the piston downwards with additional acceleration, which increase the power produced by the engine.

In an opposed-piston engine, a piston has a top land. The piston top land has a non-cylindrical shape which affords more clearance with a piston bore to thrust and anti-thrust sides than to front-facing and rear facing sides.

A piston assembly includes a piston head for reciprocating back and forth within a cylinder of an engine, an upper rod coupled to the piston head at one longitudinal end of the upper rod and fixed relative to the piston head, and a lower rod rotatably coupled to an opposite longitudinal end of the upper rod, the lower rod configured to pivot about the opposite longitudinal end of the upper rod. The lower rod is configured to couple to a crankshaft at a longitudinal end of the lower rod opposite the upper rod. Methods of forming a piston assembly and engines incorporating such piston assemblies are also disclosed.