A rotary valve internal combustion engine has a piston connected to a crankshaft, where the piston is reciprocatable in a cylinder, and a combustion chamber being defined in part by the piston. The engine has a rotary valve rotatable in a valve housing fixed relative to the cylinder, the rotary valve having a valve body containing a volume defining, in part, the combustion chamber and further having in a wall part thereof a port giving, during rotation of the valve, fluid communication successively to and from the combustion chamber via inlet and exhaust ports in the valve housing. The valve body has a non-uniform radial profile along its axial length and/or about its axis of rotation to accommodate changes in the profile of the valve body during operation to maintain a substantially constant clearance between the valve body and the housing throughout the length of the valve body.

A split-cycle engine includes: a first cylinder housing a first piston, wherein the first piston performs an intake stroke and a compression stroke, but does not perform an exhaust stroke; a second cylinder housing a second piston, wherein the second piston performs an expansion stroke and an exhaust stroke, but does not perform an intake stroke; and a valve chamber housing a valve, the valve comprising an internal chamber that selectively fluidly couples to the first and second cylinders, wherein the valve and internal chamber move within the valve chamber and relative to the first and second cylinders.

A split-cycle engine includes: a first cylinder housing a first piston, wherein the first piston performs an intake stroke and a compression stroke, but does not perform an exhaust stroke; a second cylinder housing a second piston, wherein the second piston performs an expansion stroke and an exhaust stroke, but does not perform an intake stroke; and a valve chamber housing a valve, the valve comprising an internal chamber that selectively fluidly couples to the first and second cylinders, wherein the valve and internal chamber move within the valve chamber and relative to the first and second cylinders.

A two-stroke internal combustion engine has a crankshaft disposed at least in part in a crankcase, and a cylinder block connected to the crankcase and defining a cylinder. The cylinder defines at least one exhaust port for discharging exhaust fluid. A piston is movably disposed within the cylinder and is operatively connected to the crankshaft. The piston is movable along a cylinder axis in a reciprocating motion including an upstroke and a downstroke. An exhaust valve assembly is operatively connected to and rotates with the crankshaft. The exhaust valve assembly has a shaft rotatably supported by the cylinder block and a valve configured to cyclically obstruct the exhaust port. The valve is operable to move clear of the exhaust port before the piston uncovers the exhaust port during its downstroke, and at least partially close the exhaust port before the piston fully covers the exhaust port during its upstroke.

Apparatus for controlling valve timing in an internal combustion engine locates a first valve port in a first side of the engine cylinder and a second valve port in a second side of the engine cylinder. A first rotating valve disc and a second rotating valve disc are respectively disposed next to the first and second valve port. Each rotating valve disc includes a valve port. Each disc rotates in synchronism with the crankshaft to align its' port with the respective first and second valve ports. A variety of intake devices coupled to the first rotating valve disc control intake air flow into the engine cylinder, and a variety of exhaust devices coupled to the second rotating valve disc control exhaust gas flow from the engine cylinder.

A reciprocating cylinder seal assembly (10, 10) has an elastomeric seal, where separate inner (16, 16) and an outer (18, 18) valve seal retainers are located within the reciprocating cylinder seal assembly. The reciprocating cylinder seal assembly (10, 10) better controls radial run out than past seals in reciprocating cylinder engines. Further, the reciprocating cylinder seal assembly may have a scraper (42) that is in contact with the outer valve seal retainer (18).

A reciprocating cylinder seal assembly (10, 10) has an elastomeric seal, where separate inner (16, 16) and an outer (18, 18) valve seal retainers are located within the reciprocating cylinder seal assembly. The reciprocating cylinder seal assembly (10, 10) better controls radial run out than past seals in reciprocating cylinder engines. Further, the reciprocating cylinder seal assembly may have a scraper (42) that is in contact with the outer valve seal retainer (18).

A valve comprising a rotor, the rotor comprising two passageways and two or more sealing faces. The valve allowing for controlling air flow between four directions. The valve can be capable of operating in a number of operation modes depending on a position of the rotor. The valve design can include a valve-housing with three ports in plane with a first plane and one port normal to the first plane. A rotary valve provides a plurality of predetermined flow modes between four ports. The valve comprises an outer layer and a rotatable inner layer. The inner layer allows for a number of different flow configurations between four ports.

A valve comprising a rotor, the rotor comprising two passageways and two or more sealing faces. The valve allowing for controlling air flow between four directions. The valve can be capable of operating in a number of operation modes depending on a position of the rotor. The valve design can include a valve-housing with three ports in plane with a first plane and one port normal to the first plane. A rotary valve provides a plurality of predetermined flow modes between four ports. The valve comprises an outer layer and a rotatable inner layer. The inner layer allows for a number of different flow configurations between four ports.

A variable port engine assembly and method of use utilizing a rotating camshaft having different sized ports that are dynamically aligned with intake, combustion, and exhaust ports and timed to open and close with appropriate engine cycles to change gas flow volumes through the combustion chamber to modify fuel efficiency and power.