Patent attributes
An internal combustion engine provided with a common rail (13) and fuel injectors (3) connected to the common rail (13). When pilot injection is performed, the injection pressure pulsates. At this time, the injection amount of the main injection fluctuates by a certain fluctuation pattern. If indicating on an abscissa a time interval from when pilot injection is started to when main injection is started and indicating on the ordinate a fluctuation amount of main injection, the fluctuation pattern of the injection amount of the main injection becomes a form contracted or expanded in the abscissa direction in accordance with the fuel properties. This characteristic is utilized to find the fluctuation amount of the injection amount of the main injection.
