A combustion engine comprises a main combustion cylinder configured to enable a piston to move therein; a main valve configured to move in the main combustion cylinder; an upper non-combustion chamber operatively adjacent to the main combustion cylinder; an upper intake valve configured to move in the upper non-combustion chamber and to communicate with an intake manifold; and an upper exhaust valve configured to move in the upper non-combustion chamber and to communicate with an exhaust manifold.

A selective-cycle engine selectively operable in a 2-cycle mode and a 4-cycle mode, the selective-cycle engine including a cylinder including a head portion and a sidewall defining a cylinder interior, a piston driven in a reciprocating fashion within the cylinder interior, a head intake port and an exhaust port each defined in the head portion, a first sidewall intake port defined in the sidewall, an exhaust valve operable to open and close the exhaust port, a head intake valve operable to open and close the head intake port, and a first sidewall intake valve operable to open and close the first sidewall intake port. The head intake valve is maintained in a closed position to close the head intake port during 2-cycle mode while the first sidewall intake valve is opened and closed to provide intake air to the cylinder interior with opening and closing of the first sidewall intake valve being separately controlled from reciprocal movement of the piston.

A selective-cycle engine selectively operable in a 2-cycle mode and a 4-cycle mode, the selective-cycle engine including a cylinder including a head portion and a sidewall defining a cylinder interior, a piston driven in a reciprocating fashion within the cylinder interior, a head intake port and an exhaust port each defined in the head portion, a first sidewall intake port defined in the sidewall, an exhaust valve operable to open and close the exhaust port, a head intake valve operable to open and close the head intake port, and a first sidewall intake valve operable to open and close the first sidewall intake port. The head intake valve is maintained in a closed position to close the head intake port during 2-cycle mode while the first sidewall intake valve is opened and closed to provide intake air to the cylinder interior with opening and closing of the first sidewall intake valve being separately controlled from reciprocal movement of the piston.

A converting mechanical system including a dual connecting rod having a top section adapted to be pivotally connected to a piston on a conventional internal combustion engine and a bottom section adapted to be connected to a crankshaft of a conventional internal combustion engine. A support surrounds each dual connecting rod and includes a retractable device. A decoupling device is adapted to be located on the crankshaft a conventional internal combustion engine. The dual connecting rod has a first working position and in which the dual connecting rod is rigid and connected to the crankshaft when the piston moves. In the second working position, the dual connecting rod disconnects the crankshaft from the piston by action of the decoupling device.

A converting mechanical system including a dual connecting rod having a top section adapted to be pivotally connected to a piston on a conventional internal combustion engine and a bottom section adapted to be connected to a crankshaft of a conventional internal combustion engine. A support surrounds each dual connecting rod and includes a retractable device. A decoupling device is adapted to be located on the crankshaft a conventional internal combustion engine. The dual connecting rod has a first working position and in which the dual connecting rod is rigid and connected to the crankshaft when the piston moves. In the second working position, the dual connecting rod disconnects the crankshaft from the piston by action of the decoupling device.

A method for operating a drive apparatus, having a reciprocating-piston engine and an exhaust-gas-driven turbocharger, of a motor vehicle, the reciprocating-piston engine being operated in a four-stroke mode during on-load operation; and the exhaust-gas-driven turbocharger having an electrical machine, in particular a media gap machine, that is operated in generator mode during overrun operation of the reciprocating-piston engine. During overrun operation, the reciprocating-piston engine is operated in a two-stroke mode.

A method for operating a drive apparatus, having a reciprocating-piston engine and an exhaust-gas-driven turbocharger, of a motor vehicle, the reciprocating-piston engine being operated in a four-stroke mode during on-load operation; and the exhaust-gas-driven turbocharger having an electrical machine, in particular a media gap machine, that is operated in generator mode during overrun operation of the reciprocating-piston engine. During overrun operation, the reciprocating-piston engine is operated in a two-stroke mode.

A method for improving the efficiency of an internal combustion engine having a cycle, for each cylinder of the engine, including intake, compression, power, and exhaust strokes, comprises inserting two strokes into the cycle in addition to the intake, compression, power, and exhaust strokes. No material other than air is introduced into each cylinder during either of the additional two strokes. A high efficiency internal combustion engine system having a cycle, for each cylinder of the engine, including intake, compression, power, and exhaust strokes, comprises a cylinder, a piston, an air intake device, a fuel injector, an exhaust valve device, a camshaft, and an electronic control unit (ECU) configured to control cylinder operation such that two strokes, in addition to the intake, compression, power, and exhaust strokes, are inserted into the cycle. No material other than air is introduced into each cylinder during either of the additional two strokes.

Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.

Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.