Arrangement for reducing fuel material slip to the atmosphere in an internal combustion piston engine with at least two cylinders and at least one turbo charger unit, the arrangement comprising: - an exhaust gas system having an exhaust gas manifold which is in connection with the cylinders through exhaust gas channels and exhaust valves, which exhaust gas system being arranged to connect a combustion chamber of each cylinder of the engine controllably by means of an exhaust valve or valves to the atmosphere via a turbine section (28.2) of the at least one turbo charger unit, - a fuel processing unit for oxidation of fuel material in the exhaust gas of the engine, - a flow path, being at least partly parallel to the exhaust gas system, which flow path opens into the exhaust gas system in the vicinity of the exhaust valve of each cylinder at a side opposite to the combustion chamber with respect to the exhaust valve, characterized in that the flow path comprises a passage which is arranged into a cylinder head of the engine, and has at least one inlet in the wall of the the cylinder head which opens into the exhaust gas channel in the vicinity of the exhaust valve at a side opposite to the combustion chamber, a cross sectional area and a form of the inlet are interrelated and are selected so that they together form an ejector-like effect so that while the exhaust valve or valves of a cylinder are open the flow of exhaust gas into the conduit is decreased to be insignificant, and while the exhaust valve or valves are closed the flow of exhaust gas into the conduit is increased to provide desired flow of unburned fuel material remaining in the portion of the exhaust gases, and that an outlet of the flow path is in connection with the downstream side of the turbine section (28.2) providing a pressure difference between the inlet and the outlet of the passage for collecting the exhaust gas containing possible unburned fuel by the flow path, and that the fuel processing unit is arranged in the flow path to receive and process fuel material in the exhaust gas. - an exhaust gas system having an exhaust gas manifold which is in connection with the cylinders through exhaust gas channels and exhaust valves, which exhaust gas system being arranged to connect a combustion chamber of each cylinder of the engine controllably by means of an exhaust valve or valves to the atmosphere via a turbine section (28.2) of the at least one turbo charger unit, - a fuel processing unit for oxidation of fuel material in the exhaust gas of the engine, - a flow path, being at least partly parallel to the exhaust gas system, which flow path opens into the exhaust gas system in the vicinity of the exhaust valve of each cylinder at a side opposite to the combustion chamber with respect to the exhaust valve, characterized in that the flow path comprises a passage which is arranged into a cylinder head of the engine, and has at least one inlet in the wall of the the cylinder head which opens into the exhaust gas channel in the vicinity of the exhaust valve at a side opposite to the combustion chamber, a cross sectional area and a form of the inlet are interrelated and are selected so that they together form an ejector-like effect so that while the exhaust valve or valves of a cylinder are open the flow of exhaust gas into the conduit is decreased to be insignificant, and while the exhaust valve or valves are closed the flow of exhaust gas into the conduit is increased to provide desired flow of unburned fuel material remaining in the portion of the exhaust gases, and that an outlet of the flow path is in connection with the downstream side of the turbine section (28.2) providing a pressure difference between the inlet and the outlet of the passage for collecting the exhaust gas containing possible unburned fuel by the flow path, and that the fuel processing unit is arranged in the flow path to receive and process fuel material in the exhaust gas.