An internal combustion engine comprising at least one cylinder (12) and a pair of opposed, reciprocating pistons (16,18) within the cylinder forming a combustion chamber (28) therebetween. The engine has at least one fuel injector (34) disposed at least partly within the cylinder, the fuel injector having a nozzle (38) that is positioned within the combustion chamber and through which the fuel is expelled into the combustion chamber, wherein the nozzle (38) is exposed directly within the combustion chamber (28).