A system, comprising: an internal combustion engine having a plurality of cylinders that receive a charge flow from an intake manifold; at least one of the plurality of cylinders comprising a primary EGR cylinder that is in flow communication with an EGR exhaust manifold, the primary EGR cylinder comprising at least one intake valve and at least one exhaust valve; remaining ones of the plurality of cylinders being in flow communication with an exhaust manifold that is flow connected to an exhaust passage that emits exhaust gas from the remaining ones of the plurality of cylinders, wherein the remaining ones of the plurality of cylinders operate with a first overlap in an open position of an exhaust valve of a respective cylinder with an open position of an intake valve of the respective cylinder at initiation of an intake stroke of the respective cylinder; wherein the primary EGR cylinder includes a first compression ratio and the remaining ones of the plurality of cylinders include a second compression ratio, characterised in that the second compression ratio is less than the first compression ratio, and in that during operation the at least one exhaust valve of the primary EGR cylinder closes before top dead center of a piston of the primary EGR cylinder, relative to an opening of the at least one intake valve of the primary EGR cylinder after top dead center of the piston of the primary EGR cylinder at initiation of an intake stroke of a piston of the primary EGR cylinder, so that a second overlap in the opening of the at least one exhaust valve and the at least one intake valve is less than zero crank angle degrees to reduce backflow of exhaust gases from the EGR manifold to the intake manifold through the at least one primary EGR cylinder. an internal combustion engine having a plurality of cylinders that receive a charge flow from an intake manifold; at least one of the plurality of cylinders comprising a primary EGR cylinder that is in flow communication with an EGR exhaust manifold, the primary EGR cylinder comprising at least one intake valve and at least one exhaust valve; remaining ones of the plurality of cylinders being in flow communication with an exhaust manifold that is flow connected to an exhaust passage that emits exhaust gas from the remaining ones of the plurality of cylinders, wherein the remaining ones of the plurality of cylinders operate with a first overlap in an open position of an exhaust valve of a respective cylinder with an open position of an intake valve of the respective cylinder at initiation of an intake stroke of the respective cylinder; wherein the primary EGR cylinder includes a first compression ratio and the remaining ones of the plurality of cylinders include a second compression ratio, characterised in that the second compression ratio is less than the first compression ratio, and in that during operation the at least one exhaust valve of the primary EGR cylinder closes before top dead center of a piston of the primary EGR cylinder, relative to an opening of the at least one intake valve of the primary EGR cylinder after top dead center of the piston of the primary EGR cylinder at initiation of an intake stroke of a piston of the primary EGR cylinder, so that a second overlap in the opening of the at least one exhaust valve and the at least one intake valve is less than zero crank angle degrees to reduce backflow of exhaust gases from the EGR manifold to the intake manifold through the at least one primary EGR cylinder.