In a combustion chamber of a piston combustion engine there is a displaceable piston that can be moved progressively up or down between an upper and a lower turning position. The displacement takes place via an electrically controlled step motor which is connected to the piston via a hydraulic link, including a hydraulic lock. The lock is deactivated during the displacement a certain number of steps up or down ordered by a motor control system, and when the displacement is ended, the lock is activated by said engine control system and the moving piston is locked in a certain position ordered by the motor control system.

As disclosed herein, a piston arrangement may include a cylinder, a piston head movable along a piston axis within the cylinder, a con rod, and a track. The con rod has a first end which is coupled to the piston head and a second end which is coupled to the track. The track is adapted to be moved relative to the cylinder and is shaped such that, as the track moves relative to the cylinder, the piston head moves in reciprocating motion along the piston axis in accordance with a path of the track. The path of the track may be shaped such that piston head displacement is non simple harmonic with respect to displacement of the track relative to the cylinder.

Implementations are disclosed herein that relate to a cylinder occupying structure. An example provides a cylinder system comprising a mechanical cylinder including an internal space in which a fluid is introduced, and a piston configured for reciprocating motion in the internal space, and a cylinder occupying structure including an insertion rod, wherein the insertion rod is variably inserted into, and retracted from, the internal space of the cylinder in correspondence with the reciprocating motion of the piston.

A variable compression ratio (VCR) internal combustion engine includes an engine block defining a cylinder and a cylinder head mounted to the engine block and defining at least a part of a combustion chamber. The engine also includes a reciprocating primary piston arranged inside the cylinder and configured to compress a mixture of air and fuel and a crankshaft arranged in the engine block and rotated by an application of a combustion force to the primary piston. The engine additionally includes a secondary piston mounted in the cylinder head, movably with respect to the combustion chamber and a mechanism configured to shift the secondary piston in the cylinder head and thereby vary a volume of the combustion chamber and a compression ratio of the engine. A vehicle employing such an engine is also disclosed.

A piston arrangement comprising a cylinder, a piston head movable along a piston axis within the cylinder, a con rod, and a track having a path; wherein the con rod has a first end which is coupled to the piston head and a second end which is coupled to the track; wherein the track is adapted to be moved relative to the cylinder and is shaped such that, as the track moves relative to the cylinder, the piston head moves in reciprocating motion along the piston axis in accordance with the path of the track; wherein the path of the track is shaped such that piston head displacement is non simple harmonic with respect to displacement of the track relative to the cylinder. Also an internal combustion engine including the piston arrangement.

Apparatuses, systems and method for utilizing multi-zoned combustion chambers (and/or multiple combustion chambers) for achieving compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in an internal combustion engine are provided. In addition, improved apparatuses, systems and methods for achieving and/or controlling compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in a Siamese cylinder internal combustion engine are provided.

Apparatuses, systems and method for utilizing multi-zoned combustion chambers (and/or multiple combustion chambers) for achieving compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in an internal combustion engine are provided. In addition, improved apparatuses, systems and methods for achieving and/or controlling compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in a Siamese cylinder internal combustion engine are provided.

Disclosed is a procedure to minimize NOx during varying engine loads in a 4-stroke diesel engine including at least one cylinder with a cylinder head, first piston on a connecting rod, one actuator mounted on the cylinder head and one of the actuator operated second piston lockable via a hydraulic circuit in various positions in a combustion chamber. The second piston, at the latest during the current compression stroke is actuated by the actuator and locked in the combustion chamber, where it by the first piston introduced air is compressed in a predetermined compression ratio to meet an existing engine load wherein the free operated inlet valve is brought to close the inlet stroke at a piston position where the volume of the combustion air as introduced at the end of the compression stroke gives the predetermined compression ratio and that the injector injects the stated amount of fuel.

Apparatuses, systems and method for utilizing multi-zoned combustion chambers (and/or multiple combustion chambers) for achieving compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in an internal combustion engine are provided. In addition, improved apparatuses, systems and methods for achieving and/or controlling compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in a Siamese cylinder internal combustion engine are provided.

There is provided an internal combustion engine, provided with a crankshaft and one or several cylinders provided on the wall thereof with exhaust ports and closed at the top by a cylinder head provided with intake ports; each cylinder accommodating an engine piston connected to the crankshaft and a coaxial auxiliary piston opposite the engine piston, defining an intake chamber and a combustion chamber; said auxiliary piston axially determining on the side of the combustion chamber a housing that communicates with the intake chamber via transfer ports, the housing of which includes a secondary piston which opens and closes the transfer ports in a back-and-forth movement between a rear position and a forward position.