Patent Document ID: 20080004785
Application ID: 11819033
Patent Flag: 0

Claim One:
1. A learning method comprising: a calculation step of calculating a fluctuation correction value for inhibiting rotation fluctuation of an output shaft of a multi-cylinder internal combustion engine among cylinders of the engine when fuel injection is performed in the engine with injectors; a fluctuation inhibition step of reflecting the fluctuation correction value in operation of the injector; and a learning step of learning a deviation of an injection characteristic of the injector for each operation range of the engine in accordance with the fluctuation correction value while preventing a learning time of the deviation of the injection characteristic of the injector from exceeding a threshold, wherein the learning step includes: a convergence determination step of determining whether the fluctuation correction value has converged; a completion step of completing the learning in a certain operation range by performing the learning when the convergence determination step determines that the fluctuation correction value has converged in the certain operation range; and a carry-over step of adding a lead time of the completion of the learning before a schedule time, which is decided by the threshold, to a threshold of an operation range, in which the learning is not yet performed, if the completion of the learning precedes the schedule time.