An internal combustion engine arrangement comprising: - at least one combustion cylinder ; - a first and a second expansion cylinder, each of the first and second expansion cylinders being arranged in downstream fluid communication with the at least one combustion cylinder for receiving combusted exhaust gas via a respective inlet valve of the first and second expansion cylinders; wherein the internal combustion engine arrangement comprises an interconnection conduit between an outlet of the first expansion cylinder and an outlet of the second expansion cylinder , and an engine aftertreatment system , the engine aftertreatment system being arranged in fluid communication with the interconnection conduit , characterized in that the outlet of the first expansion cylinder is further arranged in fluid communication with an exhaust gas recirculation (EGR) conduit for delivery of a flow of combusted exhaust gas to an intake passage of the internal combustion engine arrangement, and wherein the second expansion cylinder comprises a reducing agent injection device for controllably delivery of a reducing agent into the second expansion cylinder , wherein the interconnection conduit comprises a void volume comprising a flow restriction arrangement for reducing the flow turbulence within the void volume, the EGR conduit being connected to the interconnection conduit at a position between the outlet of the first expansion cylinder and the void volume of the interconnection conduit, and wherein the engine aftertreatment system is connected to the interconnection conduit at a position between the void volume and the outlet of the second expansion cylinder . - at least one combustion cylinder ; - a first and a second expansion cylinder, each of the first and second expansion cylinders being arranged in downstream fluid communication with the at least one combustion cylinder for receiving combusted exhaust gas via a respective inlet valve of the first and second expansion cylinders; wherein the internal combustion engine arrangement comprises an interconnection conduit between an outlet of the first expansion cylinder and an outlet of the second expansion cylinder , and an engine aftertreatment system , the engine aftertreatment system being arranged in fluid communication with the interconnection conduit , characterized in that the outlet of the first expansion cylinder is further arranged in fluid communication with an exhaust gas recirculation (EGR) conduit for delivery of a flow of combusted exhaust gas to an intake passage of the internal combustion engine arrangement, and wherein the second expansion cylinder comprises a reducing agent injection device for controllably delivery of a reducing agent into the second expansion cylinder , wherein the interconnection conduit comprises a void volume comprising a flow restriction arrangement for reducing the flow turbulence within the void volume, the EGR conduit being connected to the interconnection conduit at a position between the outlet of the first expansion cylinder and the void volume of the interconnection conduit, and wherein the engine aftertreatment system is connected to the interconnection conduit at a position between the void volume and the outlet of the second expansion cylinder . <EOS>