An internal combustion engine comprising at least one pair of opposed, reciprocating pistons forming a combustion chamber therebetween a crankshaft driven by the pistons via respective drive linkages. The outer piston furthest from the crankshaft comprises a skirt extending from its perimeter towards the crankshaft to form a cylinder within which the other, inner piston reciprocates.

An internal combustion engine comprising at least one pair of opposed, reciprocating pistons forming a combustion chamber therebetween a crankshaft driven by the pistons via respective drive linkages. The outer piston furthest from the crankshaft comprises a skirt extending from its perimeter towards the crankshaft to form a cylinder within which the other, inner piston reciprocates.

In accordance with one exemplary embodiment of the present disclosure, a method for providing overspeed protection for a gas turbine engine is provided. The gas turbine engine may include an engine core and an engine shaft. The method may include determining an overspeed condition of the engine. The overspeed condition may be indicative of an above normal rotational speed of the engine shaft. The method may also include reducing an airflow through the engine core of the gas turbine engine in response to the determined overspeed condition to reduce the rotational speed of the engine shaft.

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.

An internal combustion engine for providing a linear reciprocating movement of an output shaft along a longitudinal axis. The engine has a double sided cylinder that is bounded by an engine head at each side of the cylinder. An exhaust unit is positioned at each side of the cylinder. A piston is positioned within a cylinder inner space and freely slides with respect to the cylinder along the longitudinal axis. Two piston rods are aligned with the longitudinal axis. Each piston rod is connected at a different side of the piston. Each of the piston rods has exhaust openings.

An internal combustion engine for providing a linear reciprocating movement of an output shaft along a longitudinal axis. The engine has a double sided cylinder that is bounded by an engine head at each side of the cylinder. An exhaust unit is positioned at each side of the cylinder. A piston is positioned within a cylinder inner space and freely slides with respect to the cylinder along the longitudinal axis. Two piston rods are aligned with the longitudinal axis. Each piston rod is connected at a different side of the piston. Each of the piston rods has exhaust openings.