Method and device for the diagnosis of the cylinder-selective uneven distribution of a fuel-air mixture fed to the cylinders of an internal combustion engine

Abstract

With an internal combustion engine () there is the problem that the fuel-air mixture directed into the combustion chamber of the cylinders () can be substantially influenced by manufacturing tolerances and ageing of the fuel injectors and uneven distribution is thus created. The uneven distribution is individually determined for each cylinder () depending on the operating mode of the internal combustion engine () (homogenous operation, stratified operation), wherein either the exhaust gas is analyzed and a corresponding emission value is determined therefrom or that a value is individually determined for each cylinder () for the operational roughness of the internal combustion engine (). These values are compared with a limit value predetermined for the internal combustion engine () and upon exceeding of the predetermined limit value a fault entry in a fault memory () is made for the cylinder () concerned.