MOTOR VEHICLE INTERNAL COMBUSTION ENGINE AND METHOD FOR OPERATING A MOTOR VEHICLE INTERNAL COMBUSTION ENGINE

摘要

The invention relates to a method for operating a motor vehicle internal combustion engine comprising an exhaust train (6) having an exhaust gas cleaning unit (16) which acts catalytically and/or by filtration. Supplementary combustion air is fed to the combustion chambers (3) of the internal combustion engine (1) by exhaust gas branching off from the exhaust train (6) at a total exhaust gas return rate (rAGR). Said total exhaust gas return rate (rAGR) has a low pressure part (fND) branching off downstream from the exhaust gas cleaning unit (16) and a high pressure part branching off upstream from an exhaust gas turbocharger turbine (14; 15) arranged in the exhaust train (6). According to the invention, for at least approximately the same operating points of the internal combustion engine (1) and with increased operating time of the exhaust gas cleaning unit (16), a substantially reducing low pressure part (fND) is set. The invention also relates to a motor vehicle internal combustion engine comprising an air supply system (5) for supplying combustion air to the internal combustion engine (1) and an exhaust train (6) for admitting exhaust gas from the internal combustion engine (1), in which an oxidation catalyst (34), a particle filter (35) and an SCR catalyst (36) are arranged behind each other in the direction of flow of the exhaust gas, a high pressure exhaust gas return line (27) and a low pressure exhaust gas return line (24) being provided for returning the exhaust gas from the exhaust train (6) to the air supply system (5) and adjusting means being provided for adjusting the amount of exhaust gas returned to the air supply system (5).