Patent attributes
A fuel injection controller performs minute injection amount learning for learning an injection characteristic of an injector related to a minute amount injection such as a pilot injection by performing n-times of injections of fuel amounts obtained by equally dividing a fuel injection amount required during idle rotation speed control. The controller performs relative injection amount learning for learning a variation in the injection characteristics among cylinders based on a correlation between output torque of an engine and the injection amount when the injections of the equally-divided fuel amounts are not performed. Learning areas of the minute amount injection learning and the relative injection amount learning are defined by the injection amount and fuel pressure such that the learning areas do not interfere with each other.
