Patent ID: 8793997

Claim:
A method for operating an internal combustion engine ( 10 ) with at least one high pressure and one low pressure exhaust gas turbocharger ( 22 , 24 ) and comprising on an exhaust gas side ( 50 ) of the internal combustion engine ( 10 ) turbines ( 62 , 68 ) arranged in series in an exhaust gas line of the internal combustion engine ( 10 ) including a high pressure exhaust gas recirculation line ( 74 ) and a low pressure exhaust gas recirculation line ( 80 ), for recirculating exhaust gas to an intake side ( 34 ) of the internal combustion engine ( 10 ) subject to an operating state of the internal combustion engine ( 10 ), with a switching threshold ( 104 ) provided in a speed range of the internal combustion engine ( 10 ), wherein a switch from a recirculation of the exhaust gas by way of the low pressure exhaust gas recirculation line ( 80 ) to a recirculation of the exhaust gas by way of the high pressure exhaust gas recirculation line ( 74 ) and by way of the low pressure exhaust gas recirculation line ( 80 ) is established, the method comprising the steps of: switching from a recirculation of the exhaust gas by way of the low pressure exhaust gas recirculation line ( 80 ) to a recirculation of the exhaust gas by way of the high pressure exhaust gas recirculation line ( 74 ) and by way of the low pressure exhaust gas recirculation line ( 80 ) upon reaching a switching threshold ( 104 ) in a speed range 1000≦rpm≦2000; recirculating the exhaust gas in a speed range of the internal combustion engine ( 10 ) below the switching threshold ( 104 ) exclusively by way of the low pressure exhaust gas recirculation line ( 80 ); in a speed range of the internal combustion engine ( 10 ) above the switching threshold ( 104 ), recirculating the exhaust gas in a combined manner by way of the high pressure exhaust gas recirculation line ( 74 ) and by way of the low pressure exhaust gas recirculation line ( 80 ); and in an upper speed range or load range of the internal combustion engine ( 10 ) recirculating the exhaust gas exclusively by way of the high pressure exhaust gas recirculation line ( 74 ).