An internal combustion engine system includes at least one combustor, a compressor arranged to compress air, an air guide arranged to guide compressed air from the compressor to at least one of the at least one combustor, an expander arranged to expand exhaust gases from at least one of the at least one combustor and to extract energy from the expanded exhaust gases, and an exhaust guide arranged to guide exhaust gases from at least one of the at least one combustor to the expander, wherein the exhaust guide is at least partly integrated with the air guide.

An internal combustion engine wherein at least two cylinders continuously communicate via the cylinder head and wherein the connecting rod in one cylinder is offset from the connecting rod in the second cylinder by a first angle between 8 and 12 degrees as measured from the crankshaft, and a camshaft having a second offset of one half of the first angle offset.

An internal combustion engine wherein at least two cylinders continuously communicate via the cylinder head and wherein the connecting rod in one cylinder is offset from the connecting rod in the second cylinder by a first angle between 8 and 12 degrees as measured from the crankshaft, and a camshaft having a second offset of one half of the first angle offset.

An internal combustion engine and a method of controlling an internal combustion engine are provided, that are more efficient than existing engines. The internal combustion engine includes a combustion chamber, and the engine is configurable to operate in: a compressionless operating mode where the engine is driven by combustion of fuel and oxidant in the combustion chamber without compression of the fuel and oxidant; and a compression generating operating mode where the engine is used to compress fluid in the combustion chamber.

An internal combustion engine and a method of controlling an internal combustion engine are provided, that are more efficient than existing engines. The internal combustion engine includes a combustion chamber, and the engine is configurable to operate in: a compressionless operating mode where the engine is driven by combustion of fuel and oxidant in the combustion chamber without compression of the fuel and oxidant; and a compression generating operating mode where the engine is used to compress fluid in the combustion chamber.

An internal combustion engine system includes a combustor arranged to repetitively receive air and fuel, combust the received air and fuel, and expand the combusted air and fuel, an expander including a cylinder and a piston arranged to reciprocate in the cylinder, the piston being connected to a crankshaft of the engine system, and an exhaust guide arranged to guide exhaust gases from the combustor to the expander, wherein the system is arranged to provide an injection of fuel into the exhaust guide and/or arranged to provide an injection of fuel into the combustor after a combustion in the combustor and before a reception of air and fuel in the combustor for a subsequent combustion.

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 single-shaft dual expansion internal combustion engine includes an engine block, a cylinder head and a crankshaft. First and second power pistons are moveable in first and second power cylinders and are connected to first and second crankpins of the crankshaft. An expander piston is moveable in an expander cylinder and is connected via a multi-link connecting rod assembly to a third crankpin of the crankshaft. A first balance shaft is arranged in a first longitudinal opening in the engine block, and a second balance shaft is arranged in a second longitudinal opening in the engine block. The first and second balance shafts have first and second counterweight portions, respectively, and the crankshaft has a third counterweight portion causing an imbalance in the crankshaft.

A single-shaft dual expansion internal combustion engine includes an engine block, a cylinder head and a crankshaft. First and second power pistons are moveable in first and second power cylinders and are connected to first and second crankpins of the crankshaft. An expander piston is moveable in an expander cylinder and is connected via a multi-link connecting rod assembly to a third crankpin of the crankshaft. A first balance shaft is arranged in a first longitudinal opening in the engine block, and a second balance shaft is arranged in a second longitudinal opening in the engine block. The first and second balance shafts have first and second counterweight portions, respectively, and the crankshaft has a third counterweight portion causing an imbalance in the crankshaft.

A combustion engine comprises combustion chambers (1-4) with reciprocating pistons (5), intake ports (6) and exhaust ports (7). Overflow ports (11,12) are provided between adjacent combustion chambers to provide an overflow channel (15,16) that closes during a high load mode of operation of said engine and opens during a partial load mode of operation. The overflow ports (11,12) straddle a path of shortest distance between adjacent combustion chambers and said overflow channel (15) extends at least substantially along said path of shortest distance. In a further aspect of the invention, exhaust ports (1b+2a, 3b+4a) of adjacent combustion chambers are joined into a common exhaust channel (P2,P4) that communicates with an exhaust header (20) of the engine through valve means (V1,V2) that open during the high load mode of operation of said engine and close during a partial load mode of operation.