Method and apparatus for determining the optimum ignition cylinder cut-off profile

In one aspect, a cylinder cut-off engine control unit is described. The cylinder cut-off engine control unit comprises a Zylinderabschaltmodul which is adapted to determine an ignition portion for operation and a load associated cylinder for the supply of a desired engine output. The cylinder cut-off engine control unit also includes an ignition control unit which is adapted to control ignition in a manner to be switched off in the cylinder, which provides the selected firing fraction for operation. Various methods, modules, look-up tables and arrangements in connection with the selection of a suitable firing fraction for the operation are also described.