Internal combustion engine with cylinder deactivation and methods of cylinder deactivation

The invention relates to an internal combustion engine with several cylinders, which are grouped in a first and a second group of cylinders, wherein the cylinders of the second cylinder group can be switched off in a partial load operation of the engine, and with a first (5, 6) and a second exhaust gas treatment device (7, 8) which are arranged in parallel. According to the invention there is a common exhaust pipe (2) for the exhaust gases of the two cylinder groups, which branches into a first line branch (3) to the first exhaust gas treatment device (5, 6) and a second branch line (4) branches off to the second exhaust gas treatment device, wherein the second exhaust gas treatment device (7, 8) a larger exhaust gas purification capacity per cylinder than the first exhaust gas treatment device (5, 6). In addition, a means (10) for closing the second line branch (4) is provided.