Patent ID: 7946280

Claim:
A method of operating an internal combustion engine having at least two cylinders capable of operating with anyone of a fuel of variable quality stored in a tank or with and a fuel blend stored in the tank, wherein the fuel blend is mixed in a variable ratio from a first and at least a second fuel, and wherein the fuel of variable qualities and the fuel blends of different compositions either require a variable air/fuel ratio for the achievement of a stable combustion or have a variable vaporization behavior, the method comprising: varying a quantity of fuel delivered to the at least two cylinders in at least one of the cylinders to supply one of a lean and a rich air/fuel mixture, wherein the fuel quantity variation is individually adjusted to each of the at least two cylinders; evaluating the effect of the fuel quantity variation on at least one of a starting characteristic and a running smoothness of any one of each of the at least two cylinders and the internal combustion engine; and implementing a fuel adaptation for all cylinders based on the fuel quantity variation achieving an improvement in at least one of the starting characteristic and the running smoothness.