INJECTOR FAILURE DIAGNOSIS METHOD AND INJECTOR FAILURE DIAGNOSIS DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an injector failure diagnosis method and an injector failure diagnosis device capable of detecting a state in which fuel cannot be injected from an injector due to fixation, clogging or the like of the injector.SOLUTION: An injector failure diagnosis method for an engine including a plurality of injectors for injecting fuel to a plurality of cylinders, respectively, comprises: setting a first combination group and a second combination group so as to prevent combinations of two cylinders from overlapping each other; setting a diagnosis order so as to contain one cylinder common to the two combinations of paired cylinders continuous in diagnosis time series; simultaneously stopping injection of the first combination group during idling, simultaneously stopping injection of the second combination group after measuring an indicated fuel injection quantity on the increase if the fuel cannot be injected, and determining the cylinder for which the corresponding injector fails from a change in the indicated fuel injection quantity; comparing the cylinder determined to fail out of the cylinders in the first combination group with the cylinder determined to fail out of the cylinders in the second combination group, and identifying the cylinder common to the first combination group and the second combination group as a fault cylinder.