Internal combustion engine system

A spark-ignition internal combustion engine (ICE) system for a vehicle, the spark-ignition ICE system comprising:

• a two-stroke ICE operable on a gaseous fuel or a liquid fuel, the two-stroke ICE having at least a pair of first and second cylinders with corresponding first and second cylinder walls,
• the first cylinder accommodating a reciprocating first piston operable between a bottom dead center and a top dead center, and further at least partly defining a first combustion chamber with a top end of the first piston, wherein the first cylinder further comprises an ignition source arranged in the first combustion chamber, at least one intake port arranged at a top end of the first cylinder and in fluid communication with the first combustion chamber, wherein a flow of combustible gas through the at least one intake port is controllable by an intake control valve, and further an exhaust port arranged distal from the top end of the first cylinder, such that the at least one intake port and the exhaust port are located at different positions and separated by the first piston top end when the first piston is in its top dead center,
• the second cylinder accommodating a reciprocating second piston operable between a bottom dead center and a top dead center, and further at least partly defining a second combustion chamber with a top end of the second piston, wherein the second cylinder further comprises a corresponding ignition source arranged in the second combustion chamber, at least one corresponding intake port arranged at a top end of the second cylinder and in fluid communication with the second combustion chamber, wherein the flow of combustible gas through the at least one corresponding intake port is controllable by a corresponding intake control valve, and further a corresponding exhaust port arranged distal from the top end of the second cylinder, such that the at least one corresponding intake port and the corresponding exhaust port are located at different positions and separated by the second piston top end when the second piston is in its top dead center,
• the pair of first and second cylinders being arranged separated from each other with a crank angle of 180 degrees, and
• an air intake duct comprising a positive displacement device configured to receive and feed intake air to the at least one pair of first and second cylinders, the positive displacement device further being arranged in the air intake duct to separate an upstream intake tract from a downstream plenum of the air intake duct, the downstream plenum being in fluid communication with each one of the first and second cylinders of the at least one pair of first and second cylinders.