The invention provides an internal combustion engine comprising a piston mounted for reciprocating linear motion within a cylinder along a cylinder axis. The piston is coupled to an output shaft by a power transfer assembly arranged to convert linear motion of the piston to rotary motion of the output shaft. The piston has a first head moveable within a first chamber and a second head opposite the first head and moveable within a second chamber. The power transfer assembly has a lubrication system for lubricating moving components of the power transfer assembly. The lubrication system is sealed from the first chamber and the second chamber to prevent the passage of fluid from the lubrication system into the first chamber and the second chamber.

A port belt arrangement for use in a two-stroke internal combustion engine containing a pair of adjacent cylinders. The arrangement including a first hollow annulus defining a first annular channel, the first annular channel tapering in a radial direction, with increasing circumferential distance from a first port, an inner wall of the first annular channel having a second port, and a second hollow annulus defining a second annular channel, the second annular channel tapering in a radial direction, with increasing circumferential distance from a third port, an inner wall of the second annular channel having a fourth port, wherein the first hollow annulus and the second hollow annulus are joined together at a joining point located on each of their circumferences. The cross-sectional area of the first annular channel at the joining point is less than the cross-sectional area of the first annular channel at the point on the circumference of the first hollow annulus which is furthest from the joining point.

A port belt arrangement for use in a two-stroke internal combustion engine containing a pair of adjacent cylinders. The arrangement including a first hollow annulus defining a first annular channel, the first annular channel tapering in a radial direction, with increasing circumferential distance from a first port, an inner wall of the first annular channel having a second port, and a second hollow annulus defining a second annular channel, the second annular channel tapering in a radial direction, with increasing circumferential distance from a third port, an inner wall of the second annular channel having a fourth port, wherein the first hollow annulus and the second hollow annulus are joined together at a joining point located on each of their circumferences. The cross-sectional area of the first annular channel at the joining point is less than the cross-sectional area of the first annular channel at the point on the circumference of the first hollow annulus which is furthest from the joining point.

A method for operating an internal combustion engine having an engine with a first number of cylinders and a second number of cylinders and a supercharger arrangement, wherein a charge air flow supplied to the engine is compressed by means of at least one compressor and at least one turbine is acted on by an exhaust gas flow discharged from the engine. In a main operating mode, the engine operates the first number of cylinders in two-stroke operation and the second number of cylinders in four-stroke operation. A scavenging gradient of the engine is greater for the cylinders operated in the two-stroke operation than for the cylinders operated in the four-stroke operation.

A method for operating an internal combustion engine having an engine with a first number of cylinders and a second number of cylinders and a supercharger arrangement, wherein a charge air flow supplied to the engine is compressed by means of at least one compressor and at least one turbine is acted on by an exhaust gas flow discharged from the engine. In a main operating mode, the engine operates the first number of cylinders in two-stroke operation and the second number of cylinders in four-stroke operation. A scavenging gradient of the engine is greater for the cylinders operated in the two-stroke operation than for the cylinders operated in the four-stroke operation.

A port belt arrangement for use in a two-stroke internal combustion engine containing a pair of adjacent cylinders. The arrangement including a first hollow annulus defining a first annular channel, the first annular channel tapering in a radial direction, with increasing circumferential distance from a first port, an inner wall of the first annular channel having a second port, and a second hollow annulus defining a second annular channel, the second annular channel tapering in a radial direction, with increasing circumferential distance from a third port, an inner wall of the second annular channel having a fourth port, wherein the first hollow annulus and the second hollow annulus are joined together at a joining point located on each of their circumferences. The cross-sectional area of the first annular channel at the joining point is less than the cross-sectional area of the first annular channel at the point on the circumference of the first hollow annulus which is furthest from the joining point.

A port belt arrangement for use in a two-stroke internal combustion engine containing a pair of adjacent cylinders. The arrangement including a first hollow annulus defining a first annular channel, the first annular channel tapering in a radial direction, with increasing circumferential distance from a first port, an inner wall of the first annular channel having a second port, and a second hollow annulus defining a second annular channel, the second annular channel tapering in a radial direction, with increasing circumferential distance from a third port, an inner wall of the second annular channel having a fourth port, wherein the first hollow annulus and the second hollow annulus are joined together at a joining point located on each of their circumferences. The cross-sectional area of the first annular channel at the joining point is less than the cross-sectional area of the first annular channel at the point on the circumference of the first hollow annulus which is furthest from the joining point.

The invention provides an internal combustion engine comprising a piston mounted for reciprocating linear motion within a cylinder along a cylinder axis. The piston is coupled to an output shaft by a power transfer assembly arranged to convert linear motion of the piston to rotary motion of the output shaft. The piston has a first head moveable within a first chamber and a second head opposite the first head and moveable within a second chamber. The power transfer assembly has a lubrication system for lubricating moving components of the power transfer assembly. The lubrication system is sealed from the first chamber and the second chamber to prevent the passage of fluid from the lubrication system into the first chamber and the second chamber.

The invention provides an internal combustion engine comprising a piston mounted for reciprocating linear motion within a cylinder along a cylinder axis. The piston is coupled to an output shaft by a power transfer assembly arranged to convert linear motion of the piston to rotary motion of the output shaft. The piston has a first head moveable within a first chamber and a second head opposite the first head and moveable within a second chamber. The power transfer assembly has a lubrication system for lubricating moving components of the power transfer assembly. The lubrication system is sealed from the first chamber and the second chamber to prevent the passage of fluid from the lubrication system into the first chamber and the second chamber.

A rotary engine includes a housing and elliptical rotors mounted to rotor shafts for rotation within a chamber of the housing. A valve disk mounted to a rotor shaft includes a port passing between first and second sides. A valve plate includes a bore defining a cylindrical sidewall for rotationally receiving the valve disk. The valve disk includes a groove disposed in a wall, and includes a ring member disposed in the groove that contacts the sidewall of the bore when the valve disk is disposed in the bore. The apparatus may include multiple valve disks disposed in separate bores to operate as exhaust or intake valves. Circumferential channels may be included in the bore sidewalls within which the ring members are disposed.